forget about this word 之, even our Chinese dont understand it well. it should be erased from the modern dictionary.

grow(original meaning) 1.之+place -go to some place 2. -someone or something 3. -this or that 4.A之B -B of A 5.adj+之+n -adj is to discrib n 6.n+之+v(如：大道之行也) -used to complete a sentence 7. (如：久而久之)-no meaning

dont make it complex

first,之always used before chairman mao takes in office,you can hardly find it now. i give you some simple examples,之means of in "the house of a dog",and also means to in"hello to you",also an appositive

之 is a very old word in Chinese. There are some terms used today like 之前, 之后, 之所以, and some idioms like 求之不得, 意料之中. Except those, we seldom use 之 in informal conversation, because an alternative can always be found to replace 之。 What Luna wrote is specific, but I'd like to give you some explanation of 之 in this phrases. 由京之沪：here 之 is a verb, means 去 到. We can also say 从北京去上海 or 从北京到上海. 求之不得：here 之 is a pronoun, means sth, which is a normal way to say "it". 意料之中：here 之 的doesn't have a exact meaning. 那是意料之中的事=那是意料中的事. Here 之 is like 的（of）. 之 is also a normal way to say 的. XX之座驾 means someone‘s horse or car, which is equal to "某某的座驾".