These three words mean 'near'. It seems около & возле are synonyms. Can the same be said for рядом?
To start here is a list of English words that are close enough to the respective Russian words that you can use as a hint
- рядом — next to
- возле — near or close
- около — around
Рядом suggests some sequence or row of objects where one is positioned next to another. Consider booking seats in a theater: место рядом с вами would assume the place immediately next to you, while место около вас might mean the place somewhere around.
Возле suggests there is a small distance between two objects but this distance may be a continuous measure. Max Vasmer suggests the word's origins are from въз-дьлѣ, so there is a certain length or distance assumed.
Около is related to the word кольцо — a ring so the meaning suggests that one object belongs to a close circle or is somewhere around.
Also рядом is different grammatically as it requires the object to be in instrumental case, while около and возле require the object to be in genitive case.
There are good usage examples in the other answers that show the difference between these terms.
- Около нуля — around zero, or около полуночи — around midnight. You can hardly use рядом in this context, and возле would not go when speaking about time.
- рядом друг с другом — next to each other. You can hardly use возле or около here.
It is really difficult to find a sentence where возле could not be replaced with около. Both words can take either the role of an adverb or a preposition, however their use as adverbs seems archaic and rarely appears in contemporary Russian.
"Возле" and "около" are indeed quite interchangeable (thanks @shabunc) when we are talking about location. Small nuance is that "около" implies more vague and potentially more distant location than “возле”. For “возле”, both objects need to be visualized together, while for "около" they do not.
For example "около метро"/"near a subway station" can mean 5-10 minutes away by foot, while "возле метро" implies a very short distance (like someone is standing right next to the entrance).
"Рядом" can be vague almost like "около" when we talk about general location (ex. "рядом с метро"), but it is very strict when we use non-ambiguous topological meaning (ex. "рядом с красной машиной"). If it is the latter, then "рядом" means "next to" - an object in closest proximity to another object.
"Возле" and "около" are quite interchangeable, with the only difference that "около" has additional meaning of designating approximate values, like in "около шести утра" (you can not say "возле шести утра").
"Рядом" is, indeed, also very close in meaning to "возле" and "около" and it's extremely difficult to strictly separate usages of all three words - at least to me. However one thing that comes to my mind is that "рядом" can be used as a standalone, self-sufficient word while this less true for "около" and even lesser for "возле".
Imagine following dialog:
Ольга: "Ты где?"
Пётр: "Я уже рядом"
You can not say just "я уже около" or "я уже возле" instead - you'd need to specify the context, like "я уже около тебя" or "я уже возле метро".
рядом: nearby, close together. Unlike the other two, can be used without subject. "Это рядом.": "It's nearby."; Can be used with multiple subjects: "Дом и дорога находятся рядом.": "The house and the road are close together.".
около: near, around. Unlike the other two, can be used with non-location subjects. E.g. "около 0": "around zero".