also: うちわねた
A joke or reference understood only by a small group, such as friends or colleagues. Often used in casual conversation.
That story is an inside joke, so other people won't get it.
Their conversation was full of inside jokes, and I couldn't follow it.
Standard mixed kanji-katakana spelling.
Variant with hiragana ねた; less common but seen.
Compound of 内輪 (uchiwa, 'private, inside a group') and ネタ (neta, 'material, topic'). The word ネタ is a reversal of 種 (tane, 'seed, source').