Common in 蕴含 ('to contain, imply'), 蕴藏 ('to hold in store, lie hidden') and 底蕴 ('deep foundation, inner substance'). It implies something rich gathered and held within.
The grass radical on top recalls the original sense of heaping up cut grass and storing it; from 'piling up plant matter' came the abstract meaning of accumulating and holding within.
Sits below the grass radical and supplies the sound: 缊 gives the reading. Its image of bundled tangled fibres also reinforces the idea of things gathered and stored up.
