Princeton's WordNet

1. starfish, sea star(noun)

   echinoderms characterized by five arms extending from a central disk

Wiktionary

1. starfish(Noun)

   Any of various asteroids or other echinoderms (not in fact fish) with usually five arms, many of which eat bivalves or corals by everting their stomach.

2. starfish(Noun)

   an anus. See also chocolate starfish.

Origin: star + fish

Webster Dictionary

1. Starfish(noun)

   any one of numerous species of echinoderms belonging to the class Asterioidea, in which the body is star-shaped and usually has five rays, though the number of rays varies from five to forty or more. The rays are often long, but are sometimes so short as to appear only as angles to the disklike body. Called also sea star, five-finger, and stellerid

2. Starfish(noun)

   the dollar fish, or butterfish

U.S. National Library of Medicine

1. Starfish

   Echinoderms having bodies of usually five radially disposed arms coalescing at the center.

• seesterAfrikaans
• نَجْم البَحْر، قِنْديل البَحْرArabic
• морска звездаBulgarian
• estrela do marPortuguese (BR)
• hvězdiceCzech
• der SeesternGerman
• søstjerneDanish
• αστερίαςGreek
• meritähtEstonian
• ستاره درياييFarsi
• meritähtiFinnish
• étoile de merFrench
• כּוֹכָב-יָםHebrew
• तारामीनHindi
• morska zvijezdaCroatian
• tengeri csillagHungarian
• bintang lautIndonesian
• krossfiskurIcelandic
• stella di mareItalian
• ひとでJapanese
• 불가사리Korean
• jūrų žvaigždėLithuanian
• jūraszvaigzneLatvian
• tapak sulaimanMalay
• zeesterDutch
• sjøstjerneNorwegian
• rozgwiazdaPolish
• estrela do marPortuguese
• stea de mareRomanian
• морская звездаRussian
• hviezdicaSlovak
• morska zvezdaSlovenian
• morska zvezdaSerbian
• sjöstjärnaSwedish
• ปลาดาวThai
• deniz yıldızıTurkish
• 海星(魚)Chinese (Trad.)
• морська зіркаUkrainian
• ستارپ ،مچھلیUrdu
• sao biểnVietnamese
• 海星（鱼）Chinese (Simp.)