noun
open reel; reel-to-reel
Refers to open-reel tape recorders or players, as opposed to cassette or cartridge types. Common in audio and vintage electronics contexts.
父はまだオープンリールのテープレコーダーを使っている。
My father still uses an open-reel tape recorder.
Variant with a middle dot, reflecting the original English word boundary.
カセットテープ is a cassette tape, which is enclosed in a plastic case, while オープンリール refers to open-reel systems where the tape is on exposed reels.
Borrowed from English 'open reel'.