Well, no. She left him at the altar.
This particular pair of homophones is one of the most troublesome, based on what I see come across my desk. Perhaps I can provide some helpful hints for telling them apart, so you’ll know which one you should be using in a given situation. We’ll see . . .
An altar is a raised surface, first of all. It could be a simple table, or a flat rock, or perhaps an elaborately constructed piece of furniture with storage space underneath, hidden behind doors or curtains. But I digress. An altar is a surface on which one puts ritual items, for the purpose of then enacting said ritual. I’ll wager most of you readers are familiar with the altar at the front of a church (Catholic, Protestant, doesn’t matter — churches have altars). I’ll also wager that a number of you are equally familiar with the pagan analog, usually set at the center of the ritual space. (Not that I’d know about that or anything . . . ::cough::) If you’re writing about a ritual, you’ll likely need to use the word altar.
Altar can be used figuratively, as well. They worship at the altar of freedom.
Alter is foremost a verb, meaning to change something. I say “foremost,” because there’s also the psychiatric usage meaning “a distinct and separate personality” when talking about people with Dissociative Identity Disorder (DID, formerly Multiple Personality Disorder [MPD]). She has fifty-four alters. However, unless you’re writing a piece on DID, you’ll probably be using the verb form and talking about something being altered. Think of “alterations” made to clothes by a tailor or a seamstress. They alter the clothing.
Alter is also the verb used to mean “to spay or neuter an animal.” The procedure changes the animal, so that it can no longer reproduce.
Alter is also the word in “alter ego,” meaning a different side of a personality or even a close friend who holds the same views as one’s own. It’s important to note, I think, that this is the common usage; we can all have alter egos, but not be diagnosed with DID. It literally means “second I.” Drinking brings out his alter ego; he’s quite the Jekyll and Hyde.
It will probably help to remember that “alter” is part of “alternative” and “alternate.” If you need a word that denotes change, something different from the expected, you want alter.
Now if you’ll excuse me, I need to alter my altar setup for the upcoming feast day.