lobster

UK: /ˈlɒbstə^r/ US: /ˈlɑbstɚ/ ,(lob′stər)

Inflections of 'lobster' (n):

lobsters

npl (All usages)

lobster

npl (Especially as a collective plural—e.g. "Lobster are expensive.")

WordReference Random House Learner's Dictionary of American English © 2025

lob•ster /ˈlɑbstɚ/   n., pl. (esp. when thought of as a group) -ster, (esp. for kinds or species) -sters. 

1. Invertebrates [countable] a saltwater crustacean that can be eaten, having eyes on stalks, eight legs, and two large pincers.
2. [uncountable] the edible meat of the lobster.

WordReference Random House Unabridged Dictionary of American English © 2025

lob•ster  (lob′stər), n., pl. (esp. collectively) -ster,  (esp. referring to two or more kinds or species) -sters. 

1. Invertebrates any of various large, edible, marine, usually dull-green, stalk-eyed decapod crustaceans of the family Homaridae, esp. of the genus Homarus, having large, asymmetrical pincers on the first pair of legs, one used for crushing and the other for cutting and tearing: the shell turns bright red when cooked.
2. Invertebrates See spiny lobster. 
3. Invertebrates any of various similar crustaceans, as certain crayfishes.
4. the edible meat of these animals.

• bef. 1000; Middle English lopster, Old English loppestre literally, spidery creature (loppe spider (see lob¹) + -stre -ster); compare lop¹

Collins Concise English Dictionary © HarperCollins Publishers::

lobster / ˈlɒbstə/ noun ( -sters, -ster)

1. any of several large marine decapod crustaceans of the genus Homarus, esp H. vulgaris, occurring on rocky shores and having the first pair of limbs modified as large pincers
2. any of several similar crustaceans, esp the spiny lobster
3. the flesh of any of these crustaceans, eaten as a delicacy

Etymology: Old English loppestre, from loppe spider