It's an SSD (Solid-State Drive). The rule for using "a" or "an" is based on pronunciation, not spelling. Since the letter "S" begins with a vowel sound, we use "an" before SSD.

It's an SSD (Solid-State Drive). The rule for using a or an is based on pronunciation, not spelling. Since the letter "S" begins with a vowel sound, we use "an" before SSD.

An SSD is a storage device containing non-volatile flash memory.

A SSD is a storage device containing non-volatile flash memory.

Remember, when pronounced as an individual letter, the consonant "S" sounds like "ess".

Unlike HDDs, an SSD doesn't have moving parts.

Do you know how to install an SSD?

And we say "an S", not "a S".

The acronym SSD begins with an S.

The following phrases contain abbreviations that start with the consonant "S" but are commonly pronounced as separate letters; consequently, they take the indefinite article "a":

• an SEO (Search Engine Optimization)
• an SLA (Service-Level Agreement)
• an SMS (Short Message Service)
• an SMTP (Simple Mail Transfer Protocol)
• an STD (Sexually Transmitted Disease)
• an SUV (Sport Utility Vehicle)
• an SVG (Scalable Vector Graphics)