tortoise

From Middle English tortuse, tortuce, tortuge, from Medieval Latin tortuca, of uncertain origin. May be from Late Latin tartarūcha, from tartarūchus, from Ancient Greek ταρταροῦχος (tartaroûkhos, literally "holder of Tartarus" [the land of the damned dead in Greek myths]), because it used to be thought that tortoises and turtles came from the underworld and they were commonly paired with such infernal beasts

daisy

From Middle English dayesye, from Old English dæġes ēage (“daisy”, literally “day's eye”) due to the flowers closing their blossoms during night.

tölva

Icelandic for computer. A portmantau word, coined from tala (number) and völva (prophetess)

comet

From Middle English comete, from Latin cometes, from Ancient Greek κομήτης (komḗtēs, “longhaired”), short for ἀστὴρ κομήτης ([astēr] komētēs, "longhaired [star])"

親知らず (oyashirazu)

Japanese for wisdom teeth. Compound of 親 (oya, “parent”) +‎ 知らず (shirazu, “not know”, classical negative form of the verb 知る (shiru, “to know”), literally "unknown to parents", because wisdom teeth usually appear after moving out of the parents' home

ghost

From Middle English gost, from Old English gāst, gǣst (“breath, spirit, soul, ghost”) (compare modern English Holy Ghost), from Proto-West Germanic *gaist, from Proto-Germanic *gaistaz, from Proto-Indo-European *ǵʰéysdos, from *ǵʰéysd- (“anger, agitation”).

maelstrom

From early modern Dutch maelstrom (“whirlpool”) (obsolete) (modern Dutch maalstroom), from malen (“to whirl around; to grind”) (ultimately from Proto-Indo-European *melh₂- (“to crush, grind”)) + stroom (“stream; river; current or flow of water or other liquid”) (ultimately from Proto-Indo-European *srew- (“to flow, stream”)).

rafhlaða

Icelandic for battery. From raf- (“electro-”) + hlaða (“barn”).

muscle

From Middle English muscle, muscule, muskylle, and in part from Middle French muscle, from Latin mūsculus (“a muscle”, literally “little mouse”) because of the mouselike appearance of some muscles, from mūs (“mouse”).

卵 (tamago)

Japanese for egg. From 玉 (tama, “ball”) and‎ 子 (ko, “child, small thing”)