Broadly speaking, the distinct funding rounds in the life of a startup are:
Pre-seed or Bootstrap
This is the very first stage of funding, and usually the investors are the founders themselves, or friends and family of the founders. The pre-seed funding gives the startup just enough to get basic operations off the ground.
Seed
This is the first funding stage in which the startup seeks a formal investment from an external investor, such as an angel investor or a venture capital fund that specialises in early-stage startups.
The money raised during a seed round is often used to conduct market research, make key hires, build a minimum viable product (MVP) and test their product to prove product market fit.
Series A
Series A funding comes in when a startup can show traction in the market and that it is ready to scale. Companies typically use Series A funding to grow the team and continue developing the product and business.
Series B, C and beyond
If the company needs to raise funding to continue to grow, the next rounds are called Series B, C, D and so on.