The verb maintain has 10 senses (first 5 from tagged texts)
1. (41) keep, maintain, hold -- (keep in a certain state, position, or activity; e.g., "keep clean"; "hold in place"; "She always held herself as a lady"; "The students keep me on my toes")
2. (38) conserve, preserve, maintain, keep up -- (keep in safety and protect from harm, decay, loss, or destruction; "We preserve these archeological findings"; "The old lady could not keep up the building"; "children must be taught to conserve our national heritage"; "The museum curator conserved the ancient manuscripts")
3. (13) sustain, keep, maintain -- (supply with necessities and support; "She alone sustained her family"; "The money will sustain our good cause"; "There's little to earn and many to keep")
5. (4) wield, exert, maintain -- (have and exercise; "wield power and authority")
6. keep, maintain -- (maintain for use and service; "I keep a car in the countryside"; "She keeps an apartment in Paris for her shopping trips")
7. keep, maintain -- (maintain by writing regular records; "keep a diary"; "maintain a record"; "keep notes")
8. maintain, defend -- (state or assert; "He maintained his innocence")
9. uphold, maintain -- (support against an opponent; "The appellate court upheld the verdict")
10. observe, keep, maintain -- (observe correctly or closely; "The pianist kept time with the metronome"; "keep count"; "I cannot keep track of all my employees")