Meanings
nounindex fossil (plural index fossils)
plural index fossils
- Any ancient remains of a plant or animal that lived during a specific geological period and that can be used to date the containing rocks.
Synonyms & antonyms
nouna fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found
Similar
guide fossil
Broader
Synonym sets from Open English WordNet, CC BY 4.0.
Cite this entry
APA
index fossil. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/index%20fossil
MLA
“index fossil.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/index%20fossil. Accessed November 2, 2026.
Chicago
WatkinsX Dictionary, s.v. “index fossil,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/index%20fossil.
Source: index fossil on Wiktionary, CC BY-SA 4.0.