1. A planet with reference to its satellites, or the sun with reference to its planets.

2. The brighter star of a double star system.

A term used to distinguish basic compounds from similar or isomeric forms; in organic compounds, for example, RCH₂OH is a primary alcohol, R₁R₂CHOH is a secondary alcohol, and R₁R₂R₃COH is a tertiary alcohol; in inorganic compounds, for example, NaH₂PO₄ is primary sodium phosphate, Na₂HPO₄ is the secondary form, and Na₃PO₄ is the tertiary form.

1. One of the high-voltage conductors of a power distribution system.

2. See <<primary winding>>

1. A young shoreline whose features are produced chiefly by nonmarine agencies.

2. Of a mineral deposit, unaffected by supergene enrichment.

Of a metal, obtained directly from ore.

Of or pertaining to quills on the distal joint of a bird wing.