I know people who's primary salad is just tomatoes and cucumbers with nothing else... no salt, no pepper, no onion, no dressing, no oil... I still consider it a salad, just not a good one.

My favourite salad is good lettuce, sliced onion, salt, red wine vinegar, and olive oil. Also cucumber and onion is multiple ingredients.

A salad is at least one ingredient chopped up and tossed with some kind of dressing. This basically requires at least two ingredients. One chopped solid and one liquid dressing. Could be cucumbers and vinegar. Could be lettuce with ranch dressing. Obviously salads with more ingredients than two or three are probably gonna be better, but I think you could call cucumbers and onions chopped up and tossed with ranch a salad for sure.

Nachos are just upgraded taco salad.

I went to a party where everyone was supposed to bring a salad and vote on the best one. I brought the nachos. The vote was unanimous.

I grew up eating green salads without dressing, because the dressings my parents favored were so salty and acidic they hurt my mouth. Lettuce, sliced tomatoes, carrots, celery, maybe cucumber.

These days I usually go for a "Mediterranean" salad with greens, olives, feta or similar cheese, cucumber, tomato, bell peppers, herbs, and a splash of olive oil.

If you're making it for a group of people, finding a good mix of vegetables for a salad involves excluding the ones that someone doesn't like. I don't like zucchini or asparagus. One of my housemates can't abide celery. One friend doesn't like jicama. Another friend is okay with red bell pepper but can't abide green bell pepper. Making a salad everyone enjoys seems to be partly about getting all these preferences right and then balancing what's left.

I talked with a expert (my one friend who knows how to use a knife) and the conclusion is: any vegetable that is served in a different plate.