I asked Chagi: I might be experiencing a Mandela effect here but I want you to look past that and see if there's anything more to it. For all my life, my friends have all referred to limes - the green ones - as limónes, and lemons -the yellow ones- as limas. Recently taking a Spanish course and the green ones are called lima and the yellow ones are called limón. Is there a reason these two would get mixed up culturally or regionally or anything like that? Which one is the truth
They said: Your friends aren't misremembering — that's real Mexican usage, and your course is teaching a different (mostly peninsular/dictionary) standard. Both are "true."
Mexico and much of Latin America: limón = the green lime (Key/Persian). It's the default citrus in the cuisine, so it gets the plain, unmarked name. A yellow lemon is the marked oddity: limón amarillo or limón real.
Spain, and what textbooks teach: limón = yellow lemon, lima = green lime. RAE codifies this, so courses inherit it.
The twist on lima: in Mexico, lima usually isn't your yellow lemon at all — it's Citrus limetta, the sweet lime. Distinct fruit: pale greenish-yellow, low acid, faintly floral, often with a little nipple on top. Shows up in Christmas ponche and around Día de Muertos.
So if your friends pointed at a yellow lemon and said lima, that's probably them reaching for the nearest word for a yellowish citrus that isn't the everyday limón.
Why it split: both words came into Spanish from Arabic (laymūn, līma), which used them loosely across a whole citrus family. Different regions then pinned the words to whichever fruit was locally common. Chile calls a lime limón de Pica; parts of the Caribbean just say limón verde / limón amarillo and skip lima entirely.
Practical takeaway: in a Mexican kitchen or taquería, ask for limón and you'll get a green lime. On your Spanish exam, mark limón as yellow.
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Also I hoped to just bring this up in casual friendly conversation with you again someday but since the timer on our deadman's switch is once again approaching zero and it doesn't look like either of us is going to step in to reset it this time I'm just gonna say it now. A while back you told me that Mexicans say "aguas" to mean watch out, and I said "waters?" and you said yep exactly and nope I have no idea why; Duo taught me later on that it comes from early industrial times when people would call "aguas" before dumping wastewater from a door or window. So... Gross lol but I thought it was interesting and I have been holding onto excitement to tell you about that for a few months now, I just kept holding because I had hoped for/expected things to get better rather than worse.