A soundcard is the piece of computer hardware that turns digital data into sound you can hear, and turns sound from a microphone back into data. Originally it really was a card — a flat green board you slid into a slot inside a desktop computer, back when computers came with no sound at all beyond a beep. Today almost every computer has this built into the main board, so people mostly say 'soundcard' about an extra one you add for better quality: musicians, gamers and people who record their voice buy them. Confusingly, the name has survived past the card shape — a small box that sits on your desk and plugs in by USB is still often called a soundcard, though careful people call that an audio interface. You will also see it as two words, 'sound card', which is the more common spelling. It is a countable noun and belongs to ordinary technical talk, not formal writing.

音效卡。（電腦裡負責發聲的硬體；外接式的專業款在台灣多半叫「錄音介面」或「audio interface」。）