(Latin: of, relating to, or resembling; compound of the suffixes -ule, "little, small" and -ar, "pertaining to, of the nature of, like"; and so, -ular is a combining form meaning: referring to something "specified": appendicular, molecular, pedicular; as well as, a combining form meaning "resembling" something specified: circular, globular, tubular)

Surrounding or around a follicle.
Near or around the eye.
Situated around or near a vessel or the tissues surrounding a blood vessel.
Involving many joints, as opposed to monoarticular (affecting just one joint).
A reference to, or characterized by, pustules.
quadrangular (kwohd-RANG-you-luhr) (adjective) (usually not comparable)
Having four distinct and visible corners or bends: Squares, parallelograms, and rectangles are all quadrangular shapes of buildings or other structures.
regular (adjective), more regular, most regular
1. Concerning a religious rule: There are two kinds of clergy, a regular clergy and a secular clergy.
2. Descriptive of evenness, form, or possessing a repeated pattern; uniform: The design on the new curtains with the trees printed in regular intervals and all in green shades had a calming effect on the elderly Mrs. Jones.
3. Pertaining to a figure or item with all the sides having the same length and all the angles having the same size: The new table had a regular form which was good for the whole family to sit at.
4. Regarding something that performs at constant intervals: Dr. Page was satisfied with the regular beats of June's heart.
1. A small pouch; for example, the alveolar saccules (little air pouches) within the lungs.
2. Resembling a sac or saccule.
1. Worldly rather than spiritual.
2. Not specifically relating to religion or to a religious body: "They were playing secular music instead of sacred hymns."
3. Relating to or advocating secularism.
4. Not bound by monastic restrictions; especially, not belonging to a religious order (a reference to the clergy).
5. Occurring or observed once in an age or century.
6. Lasting from century to century.
7. Etymology: it was used in early Christian texts for the "temporal world"; as opposed to the "spiritual world"; and that was the sense in which its derived adjective Latin saecularis passed via Old French seculer into English.

The more familiar modern English "non-religious" meaning came into the language at about the 16th century.