tap-root

n chief root of a plant, growing straight downwards （植物的）主根.

tangy, tank, tankard, tanker, tanner, tannery, tannic, tannic acid, tannin, Tannoy, tantalize, tantalize, tantalise, tantalizing, tantalising, tantalizingly, tantalisingly, tantamount, tantrum, tap, tap-dance, tap-dancer, tap-dancing, tap-water, tape, tape deck, tape recorder, tape-measure, tape-recorder, tape-recording, taper, tapestried, tapestry, tapeworm, tapioca, tapir, tappet, taps, tar, taradiddle, taramasalata, tarantella, tarantula,