Definition of "maintain"
maintain
verb
third-person singular simple present maintains, present participle maintaining, simple past and past participle maintained
To keep up; to preserve; to uphold (a state, condition etc.).
Quotations
Ther[idamas]. Won with thy words, & conquered with thy lookes,I yeeld my ſelfe, my men & horſe to thee:To be partaker of thy good or ill,As long as life maintaines Theridimas.
c. 1587–1588, [Christopher Marlowe], Tamburlaine the Great. […] The First Part […], 2nd edition, part 1, London: […] [R. Robinson for] Richard Iones, […], published 1592; reprinted as Tamburlaine the Great (A Scolar Press Facsimile), Menston, Yorkshire, London: Scolar Press, 1973, (please specify the page)
This time was most dreadful for Lilian. Thrown on her own resources and almost penniless, she maintained herself and paid the rent of a wretched room near the hospital by working as a charwoman, sempstress, anything. In a moment she had dropped to the level of a casual labourer.
1918, W[illiam] B[abington] Maxwell, chapter XVII, in The Mirror and the Lamp, Indianapolis, Ind.: The Bobbs-Merrill Company
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 March, Nancy Langston, “Mining the Boreal North”, in American Scientist, volume 101, number 2, page 98
To declare or affirm (a clause) to be true; to assert.
Quotations
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."
2012 April 19, Josh Halliday, “Free speech haven or lawless cesspool – can the internet be civilised?”, in the Guardian
To keep in good condition and working order.
Quotations
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
(obsolete, transitive) To support (someone), to back up or assist (someone) in an action.
Quotations
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."And then he asked leave, and went out of his hermitage for to maintain his nephew against the mighty earl; and so it happed that this man that lieth here dead did so much by his wisdom and hardiness that the earl was taken, and three of his lords, by force of this dead man."
1485, Sir Thomas Malory, “j”, in Le Morte Darthur, book XV
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.
1726 October 28, [Jonathan Swift], “The Author Gives Some Account of Himself and Family, His First Inducements to Travel. […]”, in Travels into Several Remote Nations of the World. […] [Gulliver’s Travels], volume I, London: […] Benj[amin] Motte, […], part I (A Voyage to Lilliput), page 2