infill

Short definition from Wiktionary

Verb

1. 1
   To fill in a space, hole or gap.
2. 2
   To rededicate land in an urban environment to new construction.

Noun

1. 1
   That which fills in a space, hole or gap.
2. 2
   The redecoration of a fingernail or toenail after it has grown, to prevent an unsightly gap.
3. 3
   Alternative form of infil (“infiltration”).