What does agate mean?
An agate is a semi-precious gemstone: a variety of chalcedony, itself a form of quartz, prized for the fine, often concentric bands of color that run through it. Agates occur in many hues — gray, blue, red, green — and varieties such as moss agate, fire agate, and sardonyx are named for their distinctive patterns or inclusions. Because it is hard, takes a good polish, and is relatively abundant, agate has been carved into beads, seals, cameos, and ornaments since antiquity. The word also has two secondary senses: in printing, especially in North American newspapers, 'agate' names a small type size of roughly five and a half points traditionally used for classified ads and sports statistics; and informally, particularly among children, an 'aggie' or agate is a playing marble. The tone of the word is factual and descriptive rather than emotive, making it useful in geology, jewelry, typography, and general writing alike.
A semi-precious gemstone consisting of banded chalcedony, a variety of quartz, typically displaying concentric layers of differing colors.
"The museum displayed Roman intaglios carved from agate."
Specific varieties are usually named by prefix: moss agate, fire agate, blue lace agate.
In printing, a body of type measuring about five and a half points, traditionally used for newspaper classified advertisements and tabular matter.
"The box scores were set in agate to fit the narrow column."
This sense is chiefly North American; British printers historically used the equivalent 'ruby' size.
Informally, a playing marble, especially one made of stone or glass; shortened colloquially to 'aggie'.
"He won three aggies off his brother at recess."
Largely informal and associated with mid-20th-century childhood play.
The standard plural follows regular noun inflection. When referring to the playing marble, the colloquial form 'aggies' is common.
"Her collection included agates from Scotland, Brazil, and Montana."
The word 'agate' comes straight from the Greek name for a river in Sicily where these stones were once mined in abundance.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of agate
The word 'agate' derives from the Greek 'achates', the name given to the stone after the Achates River (now the Dirillo) in Sicily, where agates were famously found in antiquity. Latin adopted the term as 'achates', and medieval French passed it on as 'agate', from which English borrowed it in the Middle Ages. Cognate forms appear across European languages, all tracing back to the same Greek river-name origin.
How agate is actually used
Agate is a neutral, descriptive term with no strong connotations of formality or informality. In printing contexts, 'agate' as a type size is chiefly a North American newspaper term and may be unfamiliar to British readers. As a marble, the word is informal and largely generational.
Easily confused with agate
An auger is a boring tool for drilling holes, while an agate is a banded semi-precious stone — the two share a similar sound but nothing else.
An onion is an edible bulb vegetable; an agate is a mineral. The confusion arises mainly from the similar-sounding plural 'agates' versus casual speech, not from meaning.