What does chondrule mean?
A chondrule is a small, roundish grain—typically about half a millimetre to a centimetre across—composed mainly of silicate minerals such as olivine and pyroxene, set within the fine-grained matrix of certain stony meteorites known as chondrites. These beads are among the oldest solids in the solar system: they formed when dust in the primordial solar nebula was suddenly melted, perhaps by shock waves or lightning-like events, and then cooled rapidly into droplets before accreting into larger bodies. Because they have survived largely unchanged since that era, chondrules serve as a chemical and chronological archive of the solar system's earliest moments, and their internal textures allow researchers to reconstruct heating and cooling conditions more than four and a half billion years ago. The word is technical in register, used chiefly by meteoriticists, geologists, and planetary scientists, though it also appears in popular accounts of meteorites. Its adjective form is 'chondritic', describing rocks that contain such grains.
nounA small, usually spherical grain of silicate minerals found embedded in chondritic stony meteorites, formed from molten or partially molten droplets in the early solar nebula.
- A small spherical silicate grain within a chondritic meteorite, formed as a molten or partly molten droplet in the early solar system.
"When the thin section of the meteorite was viewed under the microscope, dozens of glassy chondrules came into focus like tiny frozen beads."
"Scientists believe chondrules were flash-heated in the solar nebula before being swept up into the parent bodies of meteorites."
"The size distribution of the chondrules suggested this stone had never been strongly thermally metamorphosed."
Regular plural; the standard form in all contexts.
"The slice contained hundreds of well-preserved chondrules."
Every chondrule is a solidified droplet older than Earth itself — a bead of rock that froze out of the solar nebula over four and a half billion years ago.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of chondrule
The word derives from the ancient Greek 'khondros' (χονδρός), meaning grain of seed or cartilage, and was coined in the nineteenth century following the recognition that many stony meteorites are full of rounded grains; it entered English through modern Latin scientific usage, alongside the related term 'chondrite'. It shares its root with other Greek-derived scientific words such as 'mitochondrion' and 'hypochondria'.
Related word forms
How chondrule is actually used
Strictly a technical term of meteoritics and planetary science; it is rare outside scientific literature but appears in popular science writing about meteorites. It carries a neutral, descriptive connotation. The plural 'chondrules' is far more common than the singular, since these grains are almost always discussed collectively.
Easily confused with chondrule
A chondrite is the entire stony meteorite containing the grains, whereas a chondrule is one individual millimetre-sized bead inside it.