palpable: [14] Latin palpāre meant ‘touch, stroke’ (it may be related to English feel). From it in post-classical times was derived the adjective palpābilis ‘touchable’ – whence English palpable. Other derivatives were the verb palpitāre ‘tremble, throb’ (from which English gets palpitate [17]) and the noun palpus ‘touching’ (source of English palp [19]). => palpitate[palpable etymology, palpable origin, 英语词源]
late 14c., "that can be touched," from Late Latin palpabilis "that may be touched or felt," from Latin palpare "touch gently, stroke" (see feel (v.)). Figurative sense of "easily perceived, evident" also is from late 14c. Related: Palpably.