To encourage or help to grow; to promote the growth of (a fire, plant, etc.). Also, with †forth, up. Now only with mixture of sense 3.

To keep up the heat of (fire). Obsolete. rare.

To keep (a fire) burning: cf. in, adv. 14. Also intransitive of a fire: To continue to burn.

To maintain in a worthy or effective condition; to support; to keep in repair; to keep burning.

To keep (a fire, etc.) going continuously.