Based on what's mentioned in the article ($1m ARR, 15% MoM, post demo day) I'm guessing it's talking about the first institutional money – which could be either

Based on what's mentioned in the article ($1m ARR, 15% MoM, post demo day) I'm guessing it's talking about the first institutional money – which could be either Seed or A; between $1m-$10m depending on market/geography