Synonym of at sign

The symbol @, most commonly used in e-mail addresses.

(physics, chemistry) The number of protons in an atom. Symbol: Z

(chemistry, physics) The smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons.

During nightfall.

(focus) At the least; at a minimum or lower limit. / In any event; anyway.

(physics) Former term for the more specific relative atomic mass.

A mountain range in northwestern Africa, occupying portions of Morocco, Algeria, and Tunisia.

(strictly) Belief that no deities exist (sometimes including rejection of other religious beliefs).

A bound collection of maps often including tables, illustrations or other text. / A bound collection of tables, illustrations etc. on any given subject.