IN GENERAL (that is, when they are used as negated existential quantifiers), the only difference in meaning is that "body" is more restrictive than "one": "nobody" refers to the non-existence of HUMAN individuals with a certain property, whereas "no one" may, but need not be so restricted. [Of course, there are differences in other respects; e.g. "no one" is a phrase, two words, each with its own full stress, whereas "nobody" is a single word]. Apart from that (= the more restrictive character of "nobody"), there is at least one other respect in which they are NOT fully interchangeable: "nobody" can be used as a noun in "He's a nobody", whereas "no one" cannot: "*He's a no one" is not English. In other words, "nobody" has (at least) one meaning that "no one" does not have: roughly, "person of no social relevance". Correspondingly "Somebody" can also be used as a noun, with the opposite meaning: "Is he a somebody?" = Is he a personality/a VIP? Which suggests, once more, that there are no real synonyms. If two expressions with very similar meanings exist in a certain language, there usually IS a reason for the 'duplication'. Sometimes it is difficult to find, but it is there, after all, if you look carefully enough, :-)

Nobody = никто или просто "ноль". Nobody knows where the dog maybe is - Никто не знает, где собака может быть. There is nobody there - Там никого нет. Whose pen is this? – Nobody’s. = Чья это ручка? – Ничья. No one = ни один из числа кого-то присуствующих: 1) Местоимение "no one" относится только к людям 2) "No one" употребляется как существительное I want to speak to no one - Я не хочу ни с кем говорить. No one opened the window. - Никто не открыл окно. No one could answer that question. - Никто не мог ответить на этот вопрос. В принципе "nobody" и "no one" равнозначны, и только в тех случаях, когда вы почеркиваете в выражении отсуствие или неделанье "кого-либо из них" лучше использовать "no one (of...)".