greina

Etymology
.

Verb

 * 1) to distinguish
 * 2) to interpret
 * 3) to branch off, ramify
 * 4) to analyze/analyse

Etymology
From.

Verb

 * 1) to discern, to distinguish, to separate
 * 2) * Genesis 1 (Icelandic translation)
 * Guð sagði: „Verði ljós!“ Og það varð ljós. Guð sá, að ljósið var gott, og Guð greindi ljósið frá myrkrinu. Og Guð kallaði ljósið dag, en myrkrið kallaði hann nótt. Það varð kveld og það varð morgunn, hinn fyrsti dagur.
 * And God said, "Let there be light," and there was light. God saw that the light was good, and He separated the light from the darkness. God called the light "day," and the darkness he called "night." And there was evening, and there was morning—the first day.
 * 1)  to analyse
 * 2)  to diagnose
 * 3)  to make something out, to discern

Etymology 1
According to Ihre, related to. However, compare the noun, from.

Verb

 * 1) to divide into parts
 * 2) to discern, distinguish
 * 3) to expound, tell, record
 * 4)  to branch out, be separated