also: ないぞうメモリー
noun
internal storage; internal memory
Refers to built-in storage or memory in a device, as opposed to external or removable storage. Common in specifications for computers, smartphones, and other electronics.
このスマートフォンの内蔵メモリは128GBです。
This smartphone has 128GB of internal storage.
内蔵メモリが不足しているので、SDカードを追加しました。
Since the internal memory was insufficient, I added an SD card.
Compound of 内蔵 (ないぞう, 'built-in') and メモリ (from English 'memory'). A straightforward technical term.