This is a term used in accounting and so on. Firstly, there is a company budget plan, and then each month (or week, or so on), _actuals_ are being incorporated to the plan.

See, here, e.g., under the Noun section: https://en.wiktionary.org/wiki/actual

Usually we call it an observation, and it is exactly OBSERVE command in probabilistic programming languages like Venture/Anglican, but in our plugin we have decided to try business-(accounting-)related terminology.