The definition of a "dit" name is that of any "as said" name used to differentiate between people with the same surname. There are many websites that explain how these names came about - location, personal description, personal characteristics, occupation, etc. What is important in the context of genealogy is whether or not the "dit" names ever were used on legal documents and church records as a part of the name, as opposed to just a spelling variation.
For example, Michel MOREL dit PARISIEN is the name entered on the burial record for the man who died in Montreal 1679-09-19 at the age of 35 (PRDH cert # 49060). Thus, MOREL dit PARISIEN is his "dit" name, regardless of how he got it. The only other two times he appears in the certificates are in the census of 1666 and of 1667, neither time with the dit name.
The Michel MOREL from Troyes occurs in the certificates only twice. Once was at the baptism of his son Amador (Francois) in 1671 in Trois Rivieres and no dit name is used. The second was on the marriage record of this son Francois 1696-11-05 at Montreal and no dit name was used. Thus there is no case to be made for the existance of a dit name of MOREL dit TROYES coming from this Michel. This man also did not appear in any records as MOREL dit MADORE.
The first of the MOREL dit MADORE lineage to use that dit name is the son of Michel, (Amador) Francois (Louis), b. 1671-01-18. His name appears in the records 27 times as either MOREL dit MADORE or (once) MADORE dit MOREL, including on his burial record. The next to use the MOREL dit MADORE surname was the son of Francois and Marie Roy, Louis MOREL dit MADORE b. 1711-12-20 at Lachine. PRDH (U. of Montreal) shows that Louis's is the only continuation of the MOREL dit MADORE surname and anyone who continued with it came from his line.
I previously dealt with the LABOURLIERE surname in another message.
You can verify this information online, by CD, or by book through PRDH (U. of Montreal).