# intercalation

> English word · Noun

## Definitions
1. A period inserted into a calendar as in a leap year.
2. The reversible insertion of a molecule between two others.
3. A layer introduced into a pre-existing sequence.

## Etymology
From Latin intercalō, from inter (“among”) + calō (“call out, proclaim”).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/intercalation