R help - Jun 2017 - Unit of cellsize in 'ascgen' from adehabitatMR? Spatialpoints unit?

Hello dear all,

A simple understanding question but I cannot find the answer anywhere.

I use coordiates (longitude, latitude) in my study. I created a 
SpatialPoints class from those data and then I created a grid using the 
'ascgen' command in the package 'adehabitatMR' like:

ascgen(xy,cellsize=40).

It worked out fine and my analysis is doing great. But I don't know what 
unit the 'cellsize' is. Is it the area (squaremeter), or the length of 
the border of each rastercell (meter)? Or is it some dimension that I 
cannot grasp from a geografical sense? I can't find the information 
anywhere.

Best, Dagmar