maintain

Etymology

From Middle English mayntenen, from Old French maintenir, from Late Latin manūteneō, manūtenēre (“I support”), from Latin manū (“with/in/by the hand”, ablative of manus) + tenēre (“to hold”).

verb

1. To keep up; to preserve; to uphold (a state, condition etc.).
   Mancini's men were far from their best but dug in to earn a 10th win in 11 league games and an eighth successive victory in all competitions to maintain their five-point lead at the top of the table. November 5, 2011, Phil Dawkes, “QPR 2-3 Man City”, in BBC Sport
   Reindeer are well suited to the taiga’s frigid winters. They can maintain a thermogradient between body core and the environment of up to 100 degrees, in part because of insulation provided by their fur, and in part because of counter-current vascular heat exchange systems in their legs and nasal passages. 2013-03, Nancy Langston, “Mining the Boreal North”, in American Scientist, volume 101, number 2, page 98
2. To declare or affirm (a clause) to be true; to assert.
   Pullman traditionalists will no doubt maintain that the full-service-at-every-seat principle is popular with their clientele; …. 1962 December, “A new Pullman era?”, in Modern Railways, page 362
   She maintains that the internet should face similar curbs to TV because young people are increasingly living online. "It's totally different, someone at Google watching the video from the comfort of their office in San Francisco to someone from a council house in London, where this video is happening right outside their front door." April 19, 2012, Josh Halliday, “Free speech haven or lawless cesspool – can the internet be civilised?”, in the Guardian
3. To keep in good condition and working order.
   The admirable smoothness of the riding also reflected the greatest credit on those who, despite the difficulties caused by the shortage of men and materials, have succeeded in maintaining the track in such first-class order. 1946 July and August, Cecil J. Allen, “British Locomotive Practice and Performance”, in Railway Magazine, page 213
4. (obsolete, transitive) To support (someone), to back up or assist (someone) in an action.