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."
3.To continue; not to suffer to cease or fail. "Maintain talk with the duke."
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." "What maintains one vice would bring up two children."
5.To affirm; to support or defend by argument. "It is hard to maintain the truth, but much harder to be maintained by it."