main·tain 
(mān-tān)
(mān-tān)tr.v. main·tained, main·tain·ing, main·tains
1. To keep up or carry on; continue: maintain good relations.
2. To keep in an existing state; preserve or retain: maintain one's composure.
3. To keep in a condition of good repair or efficiency: maintain two cars.
4.
a. To provide for; support: maintain a family.
b. To keep in existence; sustain: enough food to maintain life.
5. To defend or hold against criticism or attack: maintained his stand on taxes.
6. To declare to be true; affirm: maintained her innocence.
7. To adhere or conform to; keep: maintain a busy schedule.
[Middle English maintainen, from Old French maintenir, from Medieval Latin manutenēre, from Latin manū tenēre, to hold in the hand : manū, ablative of manus, hand; see man-2 in the Appendix of Indo-European roots + tenēre, to hold; see ten- in the Appendix of Indo-European roots.]
main·tain′a·bili·ty n.
main·taina·ble adj.
main·tainer n.