Maintain Main*tain, v. t. [imp. & p. p. Maintained; p. pr. & vb. n. Maintaining.] [OE. maintenen, F. maintenir, properly, to hold by the hand; main hand (L. manus) + F. tenir to hold (L. tenere). See Manual, and Tenable.] 1. To hold or keep in any particular state or condition; to support; to sustain; to uphold; to keep up; not to suffer to fail or decline; as, to maintain a certain degree of heat in a furnace; to maintain a fence or a railroad; to maintain the digestive process or powers of the stomach; to maintain the fertility of soil; to maintain present reputation. 2. To keep possession of; to hold and defend; not to surrender or relinquish. God values . . . every one as he maintains his post. --Grew. 3. To continue; not to suffer to cease or fail. Maintain talk with the duke. --Shak. 4. To bear the expense of; to support; to keep up; to supply with what is needed. Glad, by his labor, to maintain his life. --Stirling. What maintains one vice would bring up two children. --Franklin. 5. To affirm; to support or defend by argument. It is hard to maintain the truth, but much harder to be maintained by it. --South. Syn: To assert; vindicate; allege. See Assert.