Half And Half
When we use the term half we don’t always refer to 50%. When someone is called a half-wit that doesn’t mean he has half of the intelligence of a regular human. The intent is merely that he has less than 100% of normal intelligence. When a store has a half-off sale, very often items are only discounted 20%. If you complain to the manager he will explain that the half-off moniker refers to the never-used and theoretical manufacturer’s suggested retail price (MSRP). Finally, on Pesach we supposedly break the middle matzah in half, but who is able to produce two perfect halves? Machine matzah can be divided on the perfectly placed perforations, but with hand-matzah you have no such luck.
On chol hamoed Pesach and on the last days of yom tov we recite half-Hallel. Half-Hallel is more like 85% of Hallel. We just cut out 22 pesukim from the complete Hallel. Once again the term half is not used literally. Most likely the term half-Hallel originates from the fact that the two paragraphs that are skipped are pretty much the first half of two chapters in Tehillim. When we recite half-Hallel we don’t say the first 11 pesukim of kepittel 115 and 116, but we do recite the remainder. The import of half-Hallel is that it is the Hallel that contains some half-chapters, not that it is half of the original Hallel.