I've seen contracts where unusual words have their first letter in upper case. What does this happen? For example instead of "tenant" it says "Tenant" or contract" it's "Contract".
In general, it means the word has a special meaning in the context of the contract, often as a shorthand for a more complex term. For example, from the Stack Exchange terms of service
The Stack Exchange Network (the "Network") is a set of related Internet sites and other applications for questions and answers, owned and operated by Stack Exchange Inc. ("Stack Exchange"), a Delaware corporation.
This means that anywhere in the ToS where you see "Network" with a capital "N", it means "the set of related Internet sites and other applications for questions and answers, owned and operated by Stack Exchange Inc., a Delaware corporation" -- but it's much easier to simply say "Network".
You'll find the meanings of these words defined somewhere in the contract, usually in a section labeled "Definitions". If they're not defined, they don't have any special meaning.