1620s, "slow-going, slow-moving," from French tardigrade (17c.), from Latin tardigradus "slow-paced," from tardus "slow" (see tardy) + gradi "to walk, go, step" (from PIE root *ghredh- "to walk, go").
tar
tarantella
tarantula
tarbrush
tardation
tardigrade
tardy
tare
targe
target
tariff