SD

Definition

1. Signal detect: An output that indicates when a signal is present. A form of Signal Strength Indicator.
2. Secure Digital, a media format for nonvolatile external memory. The successor to the "MultiMedia Card" format, or MMC, SD card memories typically operate from 3.3V supplies with modest current requirements. SD memory cards are best known as storage for digital cameras, smart phones, and other consumer electronic devices.

Synonyms