dental dam

/D EH1 N T AH0 L D AE0 M/
noun
  1. 1

    A thin piece of e.g. latex, used in oral sex to prevent transmission of STDs

  2. 2

    A thin, flexible piece of latex or similar material used to isolate one or more teeth during some dental procedures.

Synonyms

Source: https://en.wiktionary.org/wiki/dental%20dam