Seed Capital relates to the earliest stage of financing. It may be at the idea stage to fund the first version of a product, or to fund initial product development and commercialisation. Raisings tend to be smaller and carry high risk to investors.
Early Venture Capital (roughly, Series A) is an investment in a high-growth recently established business (a startup) that is used to accelerate growth. It is often the first institutional (professional investor) investment into the company. This stage is usually when a company has a product on market, and is demonstrating some level of traction with customers.
Growth Venture capital (roughly, Series B-D) is an investment in a high-growth startup that is already generating significant levels of revenue and/or traction with customers. Usually, companies have raised one or more prior capital rounds with other professional investors. Capital raised is used to further accelerate growth and potentially enter new markets.
Later Stage rounds are capital raisings for advanced companies that are close to either an IPO (Initial Public Offering) or an acquisition. The company is usually generating substantial revenues and may be at or close to profitability. Growth is slower than earlier rounds, but still usually significant.
Distressed / Turnaround or Special Situations means investors that look for companies requiring an operational turnaround, that have capital structure issues (e.g. too much debt), or other situations that ordinary investors would find challenging. Turnaround / special situations investors are usually very flexible and look for returns through both debt and equity structures.