... maximum, an n. and the plural forms (identified by the abbreviation pl.) pl mums, or - ma appear. According to the labels, these abbreviations mean that the word is a noun and its plural can ... in Astronomy, 3 .a. and b., and another in Mathematics, 4 .a. , and b. After all meanings of the noun form are defined, the entry continues with the definition of the adjective form. The last ... law or other authority. 3. Astronomy. a. The moment when a variable star is most brilliant. b. The magnitude of the star at such a moment. 4. Mathematics. a. The greatest value assumed by a...