main¹ / mān/ • adj. chief in size or importance: a main road the main problem is one of resources. ∎  denoting the center of a network, from which other parts branch out: I am seldom at the main office.• n. 1. a principal pipe carrying water or gas to buildings, or taking sewage from them: a faulty gas main. ∎ Brit. a principal cable carrying electricity. 2. (the main) archaic or poetic/lit. the open ocean. 3. Naut. short for mainsail or mainmast.PHRASES: by main force through sheer strength.in the main on the whole; chiefly.main² • n. 1. hist. a match between fighting cocks. 2. (in the game of hazard) a number (5, 6, 7, 8, or 9) called by a player before dice are thrown.

main2 (dial.) of great size XIII; strong, mighty (surviving only in sense ‘sheer’ in phr. by m. force); (dial.) great in number or degree XIV; chief in size, extent, or order XV. Partly repr. OE. mæġen MAIN1 in comps., as mæġenfolc great company of people, mæġenstrengo great strength; partly — rel. ON. megenn, megn strong, powerful, or megin (in combination). There are many special collocations: e.g. m. chance XVI, mainland XIV, † m. sea XVI, m. drain XVIII; from these, by ellipsis. arose sb. uses of main; e.g. (1) prob. from the m. chance, a throw in the game of hazard, the most important part, etc. (now chiefly in phr. in the m.) XVI; (2) from the m. sea, the high sea XVI; (3) from m. drain, chief sewer XVIII.
Hence mainly † vigorously XIII; † greatly XIV; for the most part XVII.

main1 Main Street chiefly in the US, used in reference to the materialism, mediocrity, or parochialism regarded as typical of small-town life, from the title of a novel (1920) by Sinclair Lewis.

See also with might and main, Spanish Main.

main2 (in the game of hazard) a number (5, 6, 7, 8, or 9) called by a player before dice are thrown. Recorded from the 16th century (and also used to designate a match between fighting cocks), the word probably comes from the phrase main chance, in the original sense ‘the most important eventuality’.

See also an eye to the main chance.

main1 physical strength (surviving only in with might and m.). OE. mæġen = OS. megin, OHG. magan, megin, ON. magn, meg(i)n, f. Gmc. base *maġ- have power; see MAY1.