Augmentatives are forms of a word which express greater intensity, often in size but also in other attributes. English doesn't make extensive use of augmentatives, but uses them in prefixes. These include super-, grand-, mega- and arch-.
A few augmentatives formed with super- are supermarket, superpower and supersize. With the prefix grand-, we have grandmaster, grandparent and grandmother. The prefix arch- is used to create archrival, archenemy and archangel. Finally, mega- produces megacity, megaproject and megastore.
Compared to many languages, English doesn't use so many augmentatives. In many languages, suffixes are used to create augmentatives, but in English they are produced with prefixes. Augmentatives often convey greater size such as in supermarket but in the case of grandparent, it is greater age.