Instalment
WordNet
noun
(1) The act of installing something (as equipment)
"The telephone installation took only a few minutes"
(2) A part of a published serial
(3) A part of a broadcast serial
WiktionaryText
Noun
- Standard spelling for all senses.
Usage notes
- Both spellings common in Commonwealth countries outside the UK.
- US prefers installment.
- For British usage, the OED allows only instalment except in the sense of installation when the US spelling is a permissible alternative.