maintain

To keep up; to preserve; to uphold (a state, condition etc.).

maintain contact

maintain order

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; [...].

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."

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.

To support (someone), to back up or assist (someone) in an action.

And thenne he asked leue & wente oute of his heremytage for to mayntene his neuewe ageynst the myghty Erle and so hit happed that this man that lyeth here dede dyd so moche by his wysedome and hardynes that the Erle was take and thre of his lordes by force of this dede man.

When I left Mr. Bates, I went down to my Father; where, by the Aſſiſtance of him and my Uncle John, and ſome other Relations, I got forty Pounds, and a Promiſe of thirty Pounds a year to maintain me at Leyden: there I ſtudied Phyſick two years and ſeven months, knowing it would be uſeful in long Voyages.