It has different meanings in different sectors. Typical in desktop publishing tools, such as Xpress and InDesign, 'greeking' occurs when actual representation of letters is replaced by a stylised texture patterns. Usually this occurs at font sizes or zoom levels where it is impractical to accurately render the type on screen.

I must admit that after 20 years in publishing, I've never heard of Ipsum Lorem described as 'greek text', but I'm sure it is possible.