(Irish mythology) The god of the sea.

(computing theory) An abstract computing machine that has a finite number of possible internal states and operates on an infinite memory tape by first reading a symbol from a cell in the tape, and then, deterministically, based on that symbol and the machine’s state, writing a symbol in that cell, moving to a neighboring cell, and/or changing state.

(idiomatic) Brains; a person's ability to think. / Literal brains as a general substance. / (neuroanatomy) A collection of cell bodies and (usually) dendritic connections, in contrast to white matter.

Of a system: including both human and machine and/or their interface.

(retronym) Mail sent physically in the post, especially as compared to email.

(literally) Having living quarters in the forecastle / Describing seamen rather than officers

any of a large series of high quality, detailed maps of Great Britain produced in a variety of scales originally for military, but now for leisure or business use

(uncountable) A type of pasta in the form of short tubes; sometimes loosely, pasta in general.

(historical) Chic, fashionable, stylish; in the manner of a macaroni.

(idiomatic) A person who always agrees with their employer or superior.