Since we're in the midst of counting the Omer, over the next several days let's learn a bit about the Hebrew numbers from one to ten.
The Hebrew word for one is echad אחד. The feminine form is achat אחת. How did this unusual transformation occur? Rav Yehoshua Steinberg, in his Milon HaTanach, explains. The "proper" feminine form would be achadt אחדת, but that would be very difficult to pronounce. We see this in Shmuel I 4:19 - הָרָה לָלָת "was pregnant; about to give birth". The word appears as lalat ללת instead of ללדת laledet, because the dalet is "swallowed up" by the tav. Try saying achadt, and you'll see how easily that happens.
Klein points out that אחד is related to yachad יחד and lechud לחוד. These related words lead to a large number of adjectives with similar but distinct meanings. As I often get confused between them, I thought this would be a good place to list all the ones I can think of, and their translations. (Please feel free to add additional ones in the comments.)
- echad אחד - one, single
- achid אחיד - unified, uniform
- meuchad מאוחד - united
- ke'echad כאחד - jointly, like one
- yachad יחד - together, in unity
- yachid יחיד - sole, individual
- yechidi יחידי - alone, singular
- yechidai יחידאי - unique
- yichudi יחודי - exclusive
- meyuchad מיוחד - special
- lchud לחוד - apart, singly