liaison

Concise Oxford English Dictionary © 2008 Oxford University Press:
liaison/liˈeɪzn/

▶noun

• 1 communication or cooperation between people or organizations.

• 2 a sexual relationship, especially one that is secret.

• 3 the binding or thickening agent of a sauce.

• 4 Phonetics the sounding of a consonant that is normally silent at the end of a word, because the next word begins with a vowel.

– origin C17 (as a cookery term): from Fr., from lier ‘to bind’.