Definitions:

1. Refers to the initial period or beginning phase of an activity, project, relationship, or historical era. NOUN
   • In the early days of the civil rights movement, activists faced intense opposition.
2. Refers to the initial stages or beginning period of a particular situation, project, or undertaking. NOUN
   • In the early days of the company, they operated out of a small garage.
3. Said when you think its too soon to make a judgment about the likely results of something because a lot might still happen or change. NOUN
   • The early days of their relationship were filled with excitement and discovery.
4. Used to describe a time when something is just starting out and there is still much to develop or be determined. NOUN
   • It's still early days fr the project, so many details are yet to be finalized.

Synonyms:

• beginning period
• early phase
• formative years
• Initial stages
• start-up phase