From Middle English mayntenen, from Old French maintenir, from Late Latin manuteneo, from Latin manū + tenēre.

• IPA: /meɪnˈteɪn/, /mənˈteɪn/

maintain (maintains, present participle maintaining; simple past and past participle maintained)

1. To keep up; to preserve; to uphold (a state, condition etc.). [from 14th c.]
   • c. 1587–1588, [Christopher Marlowe], Tamburlaine the Great. […] The First Part […], 2nd edition, part 1, London: […] [R. Robinson for] Richard Iones, […], published 1592, →OCLC ↗; reprinted as Tamburlaine the Great (A Scolar Press Facsimile), Menston, Yorkshire, London: Scolar Press, 1973, →ISBN, Act I, scene ii ↗:

     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.

   • 1918, W[illiam] B[abington] Maxwell, chapter XVII, in The Mirror and the Lamp, Indianapolis, Ind.: The Bobbs-Merrill Company, →OCLC ↗:

     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.

2. To declare or affirm (a clause) to be true; to assert. [from 15th c.]
3. To keep in good condition and working order.
4. (obsolete, transitive) To support (someone), to back up or assist (someone) in an action. [14th]
   • 1485, Sir Thomas Malory, “[https://quod.lib.umich.edu/c/cme/MaloryWks2/1:17.1?rgn=div2;view=fulltext j]”, in Le Morte Darthur, book XV:

     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."

   • 1726 October 27, [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, […], →OCLC ↗, part I (A Voyage to Lilliput), page 2 ↗:

     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.

• (antonym(s) of “to keep up”): abandon

• French: entretenir
• German: unterhalten, warten, beibehalten, aufrechterhalten
• Italian: mantenere
• Portuguese: manter
• Russian: подде́рживать
• Spanish: mantener

• French: maintenir
• Portuguese: afirmar
• Spanish: mantener, sostener