plural of Abney level

A clinometer used to measure tree heights.

plural of level crossing

(military, US) A person who has qualified for "Craftsman" level of skill in the United States Air Force, with more training than "Journeyman" (five-level), but less than a "Superintendent" (nine-level)

The total chemical potential for electrons.

plural of Fermi level

A delicate level pivoted so as to tilt when two parts of a measuring apparatus come into contact with each other; used in precise determinations of lengths and in the accurate graduation of instruments.

plural of contact level

(mining) A level or drainage gallery which has a vertical shaft at each end, and acts as an inverted siphon.

A spirit level in which a glass-covered box is used instead of a tube.