- undertone, undercurrent - subdued emotional quality underlying an utterance; implicit meaning
--1 is a kind of meaning, substance
- undertide, undercurrent - a current below the surface of a fluid
--2 is a kind of current, stream
--2 is a part of tide
--2 has particulars:undertow, sea puss, sea-puss, sea purse, sea-purse, sea-poose