maintain
UK: meɪnˈteɪn | US: meɪnˈteɪn
vt. to keep in an existing state or condition
vt. to provide support or necessities for
vt. to assert or declare as true
The word "maintain" originates from Old French maintenir, combining main ("hand") and tenir ("to hold"). The literal sense was "to hold in one’s hand," later evolving metaphorically to mean "to keep in existence" or "to uphold." This reflects the physical act of grasping something to preserve it, extending to abstract concepts like supporting an argument or sustaining a system.
Regular exercise helps maintain good health.
The company maintains high standards for product quality.
He maintains that he was not at the scene of the crime.
The government maintains roads and public infrastructure.
She struggled to maintain her composure during the speech.