gran·ule 
(grănyl)
(grănyl)n.
1. A small grain or pellet; a particle.
2. Geology A rock or mineral fragment larger than a sand grain and smaller than a pebble, between 2 and 4 millimeters in diameter.
3. Astronomy One of the small, transient, luminous markings in the photosphere of the sun.
4. Biology A cellular or cytoplasmic particle, especially one that stains readily.
[Late Latin grānulum, diminutive of Latin grānum, grain; see gə-no- in the Appendix of Indo-European roots.]
- photomicrograph
- photomicrographer
- photomicrographic
- photomicrography
- photomicroscope
- photomicroscopic
- photomontage
- photomultiplier
- photomural
- photomuralist
- photon
- photonegative
- photonic
- photonics
- photonuclear
- photo-offset
- photo op
- photo opportunity
- photoperiod
- photoperiodic
- photoperiodism
- photophilic
- photophilous
- photophobia
- photophobic