obtaining the line number of a reference

[lukisi]

Hi all.
I want to use a reference of a word in a text, and obtain the line where the word is.

E.g.

001 I write a very short paragraph.
002 I write a long one that spans over 2 or
003 more lines. I put a reference in a word
004 right >>here<< , near its end.
...
020 In another part of the document I say:
021 The word <<here>> is at line >>4<<.

Please, tell me that it's possible!

--Luca