“AL” means beyond and other
Mirror from http://takeourword.blogspot.com/
We see Greek allos in other English words. There is allosaurus “other lizard,” named because its vertebrae were different from those of other dinosaurs found to date. Allegory comes from Greek allos + agoros “speak” (derived from the “open public space” sense), giving us the etymological meaning “to say something other than what one seems to be saying.” One can see how that came to mean “the use of symbols in a story, picture, etc., to convey a hidden or ulterior meaning, typically a moral or political one,” as the OED defines it today.
Greek allos goes back to a Proto-Indo-European root *al- “beyond, other.” We can just make it out in English else, which dates from Old English. It’s not quite as easy to see in other. That derives from a variant form of *al-, *an-, plus a suffix that meant “two,” giving us anthara- with the sense “other of two.” It’s a bit easier to see other in that. *Al- is also the root of Latin ultra “beyond.” Relatives of ultra include ulterior (etymologically meaning “further beyond”) and ultimate (“the furthest”).
The “other of two” derivation shows up again in alter, which English borrowed from Latin alter. John Ayto* says the etymological sense of alter is “more other” with an implied alternation between two. Altercation “argument (with another)” comes from the same source, via Latin altercari.
Alternate has the etymological sense “every other” and derives from Latin alter + –nus, an adjectival suffix. Altruisim is the odd man out. While it comes ultimately from Latin alter, it came to English from French altruisme and was coined from French autrui “somebody else, other.” The “l” from Latin alter was inserted in place of the u in a kind of hypercorrection with the knowledge of alter as the ancestor. The word was first used by Auguste Comte, the founder of the field of sociology, in 1852.
There is also an “other of more than two” sense that derives from *al-. We see this in English alien, etymologically “of or belonging to others (persons or places).” In researching this word, I learned, again from John Ayto (love that guy!), that there was a variant form, alient, but it died out. He likens it to ancient, pageant, and tyrant, which were previously ancien, pagean, and tyran until that same final t was added in the 15th century.
This was apparently a learned alteration, referring back to Latin participial forms. Alias (“other (name)”) is another in this *al- subfamily, as is alibi. The latter arose from the locative form of Latin alius “other” with the meaning “elsewhere” (“other place”), so that an alibi is etymologically one’s explanation of being “elsewhere” when a crime occurred.
Going back to the simpler “other” meaning of *al-, we find adultery. This may be unexpected, but it is thought to derive from the Latin phrase ad alterum “(approaching) another (unlawfully),” where ad means “to, toward”. Latin adulterare also had the broader sense “defile, pollute” which carried into English as adulterate.
Additional “other of two” words are parallel and parallax. Parallel means, in an etymological sense, “beside each other,” with parallel being formed from para– “beside” and allelon “each other,” which comes from that Greek term we’ve already encountered, allos. The OED defines parallaxas “difference or change in the apparent position or direction of an object as seen from two different points.” Parallaxwas formed from Greek para– + allasein“to change, exchange” from the sense “alternate” that arose from allos.
There are four other Proto-Indo-European roots known as *al- with different meanings, so do not assume all words beginning with *al- are related to the *al- discussed at length here. The second *al- (known as *al-2) has the etymological meaning of “to wander,” and *al-3 means “to grow, nourish.” *Al-4 is “to grind, mill” and *al-5 is “all.” None is as prolific a supplier of English words as our dear old *al- (known as *al-1).