Abarim Publications' online Biblical Hebrew Dictionary
The verb פרד (parad) means to divide, branch out or spread out. It's used for rivers that branch out into a delta (Genesis 2:10), for nations that branch out from a common ancestor (Genesis 25:23), for spreading wings (Ezekiel 1:11), for creating some kind of distance between people, whether geographically (Genesis 13:9) or emotionally (Proverbs 19:4).
From this verb comes the feminine noun פרדה (peruda), which literally denotes a "spreadling" or "spread out one" and is used to describe seed or grain (Joel 1:17 only). In post-Biblical Hebrew the noun פרידא (perida) came to mean pebble or berry.
An identical verb פרד (parad) is thought to mean to flee, but it might in fact be a specialized usage of the former verb. This supposed verb isn't used in the Bible and its existence is assumed to explain the otherwise challenging masculine noun פרד (pered), meaning mule, and its feminine equivalent פרדה (pirda). The challenge becomes far less formidable, however, when we realize that a herd of mules tends to spread out and is proverbially used to illustrate peace. This is in contrast to horses which illustrate war and thus the concentration of energy rather than the dispersal of it.
The verb root פרס (paras) means to break in two or divide and its noun פרסה (parsa) means hoof. The homophone verb פרש (paras) means to spread or spread out and the noun פרש (parash) means horse or horseman.