Abarim Publications' online Biblical Hebrew Dictionary
The verb ארח ('arah) means to wander, travel or keep company with. It's used only five times in the Bible: Judges 19:17, Job 34:8, 2 Samuel 12:4, Jeremiah 14:8 and 9:2.
Our verb yields the following derivations:
- The masculine noun ארח (orah) means way or path, and is used often figuratively of a direction in which one steers his life (Psalm 16:11, Isaiah 26:8).
- The feminine noun ארחה (orha) denotes a traveling company or caravan (Genesis 37:25).
- And then there is the curious feminine noun ארחה (aruha), which denotes a certain kind of meal or meal allowance. It occurs in Jeremiah 40:5, Proverbs 15:17 and 2 Kings 25:30 (=Jeremiah 52:34). None of the sources take the trouble to explain what this word is doing under the verb meaning to travel, but from the contexts it becomes clear that this meal is somewhat restricted. It's a ration, perhaps the kind of ration that a traveler would take along with him; a snack or doggy-bag.
The noun ירח (yareah) means moon. It's not clear where this noun comes from but the previous root is an excellent and oft cited candidate. After all, the moon is the most un-stationary celestial body in the sky, whereas the sun — the moon's proverbial counterpart — is the most stable (with the rest of the stars). This noun's twin noun ירח (yerah) means month.