If you do not have a driver license, do not drive a car. If you do not have a chemical background do NOT carry out any chemical experiment. Methanol is toxic!

Note Yuril's comment above, please be safe :-) Methanol is toxic and flammable - have a look at a material safety data sheet.

However, to explain what they mean...

The "mixture" - which (I guess) was "compound A dissolved in methanol" had some of the methanol evaporated from it, so that the concentration of compound A was increased. After removal of some of the methanol, compound A will not be soluble any more - it will be a saturated solution. At this point compound A will start to form solid crystals. These solid crystals could then be filtered from the remaining solution.

The normal way to safely remove a solvent such as methanol, and cause crystals of a material to form, is to use a rotary evaporator (use google to see what this is). A rotary evaporator is a common piece of equipment in chemistry laboratories.

thanks yurii for the advice and information. well i have worked in labs where we deal with chemicals (mostly inorganic chemicals) on day to day basis hence i am aware about certain practices observed for safety. btw thanks for reminding about the toxicity of methanol.

the paper which i was following was a hard core organic synthesis and i am new to organic synthesis especially polymerization. 

First of all, please take care according to the advice of Professor Yurii Geletii  since methanol is really toxic.

Nevertheless, I shall give a simple example about the observation you stated " The mixture was precipitated in methanol to get powder". Assume that a chemist did a reaction in which there are liquid reactants "which are miscible with a no-polar solvent used" and the final product is expected to be a solid powder but it is also soluble in that solvent. The chemist may add excess CH3OH "which is polar & non-solvent of the product" with stirring & this may precipitate the powder product from the mixture.

thanks Dr Nizar for making it clear

also Dr Fiona Smail thanks for the methodology you suggested