A micro SD card, also known as a microSD card, is a type of removable flash memory card used for storing data in portable devices. The “micro” in microSD refers to the smaller size of the card compared to standard SD cards. The full abbreviation for microSD is micro secure digital.
Micro SD cards are one of the most common storage expansion options for small, portable devices like smartphones, tablets, and action cameras. Their small size and affordability make them quite versatile and popular. But what does the abbreviation “microSD” stand for exactly?
In this article, we’ll break down the full abbreviation and meaning behind microSD cards. We’ll also provide a brief background on how these tiny memory cards came about and their most common uses today. By the end, you’ll understand exactly what the letters in “microSD” represent and why the name fits these tiny storage devices so well.
What Does MicroSD Stand For?
MicroSD is an abbreviation that stands for:
- Micro – Refers to the smaller physical size compared to a standard SD card.
- SD – Stands for Secure Digital, which is the type of memory card technology.
Put together, microSD literally means a smaller version of a Secure Digital memory card. The official logo and branding writes it as microSD or MicroSD.
Breaking Down Each Part of the Abbreviation
Micro
The “micro” portion of the abbreviation refers to the smaller physical size compared to the original SD card standard. The first microSD cards had capacities of up to 2GB and measured just 11mm x 15mm x 1mm.
That’s roughly a quarter of the size of the larger SD cards available at the time. The microSD form factor allowed the memory cards to be used in even more compact devices like mobile phones, smartphones, and smaller MP3 players.
Over time, the storage capacity of microSD cards has greatly increased while retaining essentially the same diminutive physical dimensions. Today, microSD cards are available with up to 1TB of data storage capacity in the same tiny footprint.
SD
The “SD” portion of microSD stands for Secure Digital. SD cards were originally named Secure Digital and were introduced in 1999 by the SD Association.
The Secure Digital technology offered a new design over earlier types of memory cards. It incorporated built-in security features and encryption to protect data on the card. The original SD design provided up to 2GB of storage capacity.
Since then, the SD standard has evolved to support higher capacity cards, faster data transfer speeds, and more advanced features. Some of the most common types of SD cards today include:
- SDHC – SD High Capacity cards support 4GB to 32GB capacity.
- SDXC – SD eXtended Capacity cards support 64GB to 2TB capacity.
- SDSC – SD Standard Capacity cards support up to 2GB capacity.
MicroSD uses the same Secure Digital technology standard but packs it into a much smaller physical form factor. Aside from the size difference, microSD cards support the same features and performance levels as full-size SD cards.
How MicroSD Cards Evolved
To understand how microSD came about, it helps to know the history behind SD memory cards in general:
- 1991 – Miniature Card introduced by Intel.
- 1999 – Secure Digital (SD) format created.
- Early 2000s – Devices like digital cameras, MP3 players adopt SD cards.
- 2005 – microSD specification released for smaller devices.
- 2009 – microSDHC supports up to 32GB capacity.
- 2011 – microSDXC extends capacity to 2TB.
ThemicroSD format was specifically designed for use in compact portable electronics where a full-size SD card would not fit. Some of the first devices to use microSD included mobile phones, smartphones, and GPS devices.
Since then, microSD has also become ultra-common in tablets, eReader devices, dash cams, drones, GoPros, and more. The versatility of microSD cards has allowed them to become one of the most widely used flash storage formats among consumer electronics.
Common Uses for MicroSD Cards Today
Here are some of the most popular applications and devices that utilize microSD cards for data storage and expansion today:
Smartphones
One of the earliest adopters of microSD storage was mobile smartphones. Most early smartphones like BlackBerries and Palm devices supported microSD cards in the 2000s. MicroSD allowed extra space for storing media, apps, and user data.
Many Android phones continue to support microSD expansion. iPhones do not support external microSD cards but some Android models allow up to 1TB microSD cards.
Tablets
Another hugely popular mobile device that leverages microSD storage is tablets. Most major consumer tablets from brands like Samsung, Amazon Fire, Lenovo, and Microsoft Surface allow storage expansion with a microSD card.
MicroSD slots provide a simple way to add more space for media, photos, videos, and apps beyond the built-in storage capacity. Mid-range and premium tablets typically allow up to 512GB microSD cards.
Action Cameras
Action cameras from GoPro, DJI, Insta360, and others rely on microSD cards as their primary storage medium. These rugged cameras need a compact, durable storage solution.
MicroSD cards are perfect for fitting into the slim action cam bodies while holding hours of high-resolution video. Most action cams work with up to 256GB capacity microSDXC cards.
Drones
DJI Mavic, Phantom, and Inspire drones all use microSD cards to store photos and video footage. Other camera drones also utilize microSD for mandatory onboard storage.
The small physical footprint and large storage capacities make microSD ideal for the tight confines inside a drone while offering ample space for aerial footage. Many drones allow capacities up to 128GB or higher.
Game Consoles
Gaming devices like the Nintendo Switch and Steam Deck allow the use of microSD cards to augment internal storage space. This is great for downloading digital games which can easily take up GBs of capacity.
A 512GB or 1TB microSD card lets gamers store their entire library without worrying about running out of space. MicroSD expands storage affordably compared to onboard flash solutions.
MicroSD Card Speeds and Specifications
MicroSD cards come in different speed ratings and classifications. Faster cards have higher sequential read/write speeds and minimum performance guarantees. Some key specifications include:
SD Speed Class
The SD Speed Class defines the minimum sequential write speed:
- Class 2 – Minimum 2MB/s write speed
- Class 4 – Minimum 4MB/s
- Class 6 – Minimum 6MB/s
- Class 10 – Minimum 10MB/s
UHS Speed Class
UHS (Ultra High Speed) improves burst shooting and high-resolution video recording performance:
- UHS Speed Class 1 (U1) – Minimum 10MB/s
- UHS Speed Class 3 (U3) – Minimum 30MB/s
Video Speed Class
Optimizes card performance for recording high bitrate video:
- V6 – Minimum 6MB/s
- V10 – Minimum 10MB/s
- V30 – Minimum 30MB/s
- V60 – Minimum 60MB/s
- V90 – Minimum 90MB/s
Cards with faster speed ratings typically have higher sequential read/write performance and quicker random access times for improved overall performance.
Conclusion
To recap, the abbreviation microSD stands for micro Secure Digital, referring to a miniaturized version of the SD memory card format. The advent of microSD cards provided a tiny storage medium for compact devices like mobile phones, tablets, and cameras.
MicroSD retains the same Secure Digital interface and features as full-size SD cards but crammed into a physically smaller footprint. The versatility of microSD has made it one of the most ubiquitous storage card standards across countless consumer gadgets.
So next time you use a microSD card, you’ll know that it represents an evolution of the Secure Digital memory card shrunk down into an incredible, tiny form factor – hence microSD.