protium

Fetched 2026-10-26 (cache).

Datamuse reports no synonyms or antonyms for this word.

Noun

1. {{senseid|en|Q12830437}}{{lb|en|isotope}} The [[light#Adjective|lightest]] and most [[common#Adjective|common]] [[isotope]] of [[hydrogen]], having a [[single#Adjective|single]] [[proton]] and no [[neutron]]s: {{nuclide|1|1|H}}. It is the only [[stable#Adjective|stable]] [[nuclide]] with no neutrons.
2. An atom of this isotope.

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.