Offsite, simple the process of manufacturing the superstructure in a different place from the final location of the new building. The term is most commonly used with schools, hospitals and hotel rooms. More recently, student accommodation however with general residential dwellings it is less common.
Modular construction is the process of using modules manufactured in a factory environment which are transported to site and connected together to form a complete building. This method of construction has many advantages over traditional build techniques.
Volumetric modular units are large building elements that can be linked together to form complete buildings without the need for an additional superstructure. Modules can be steel or timber-based and are pre-fitted with electrics, plumbing, heating, doors, windows and internal finishes.
Also referred to as panelised construction, this method of construction involves the manufacture of flat panels under factory conditions. Unlike volumetric construction, however, the panels are assembled on site or incorporated into existing structures.
Stick frame projects are built on top of a concrete basement or crawlspace foundation and use interior walls for support. Stick frame buildings often have more complex wall framing structures than post-frame buildings and are well known for the design and style they bring to a traditional residential home.
Timber frame construction uses timber studs and rails, together with a structural sheathing board, to form a structural frame that transmits all vertical and horizontal loads to the foundations. Platform frame is the most commonly used method in the UK.
CLT is formed of kiln-dried spruce or pine boards which are laid on top of each other at 90° (three, five, seven or nine layers depending on structural requirements), coated with a layer of polyurethane adhesive and subjected to immense hydraulic pressure to create large, stiff, dimensionally stable panels.
Although 'modern methods of construction' (MMC) is a 21st century term, it describes an approach to building properties more quickly, reliably and sustainably that has been developing over several decades. So not really very modern!
The UK have adopted definitions of different types of MMC. See the following link for more specific information. MMC
These are just some general terms used, but understanding the differences should help in making the right choices for your projects