Lowest, basic, unsophisticated level.

(idiomatic) The lowest, basic, least sophisticated level.

A clinometer used to measure tree heights.

plural of Abney level

plural of level crossing

The total chemical potential for electrons.

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

plural of Fermi level

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