also: もとねた
noun
original source; inspiration; original material
Refers to the original work, story, joke, or material that was later parodied, adapted, or used as inspiration. Often used in contexts like comedy, manga, or internet culture.
See also: ねた
このギャグの元ネタは昔のアニメだ。
The original source of this gag is an old anime.
あの曲の元ネタを知っていますか？
Do you know the original song that inspired that one?
ネタ is the material or topic itself (e.g., joke material, story seed), while 元ネタ specifically points to the original source that was used or parodied.
Compound of 元 (moto, 'origin') and ネタ (neta, 'material, seed of a story'), itself a reversal of 種 (tane). The term emerged in subcultural contexts to trace jokes or creative works back to their source.