In general, when people talk about "your score", they are talking about your current FICO score. However, there is no one score used by lenders to make decisions about you.
Credit bureau scores are not the only scores used. Many lenders use their own scores, which often will include the FICO scores as well as other information about the consumer.
FICO scores are not the only credit bureau scores. There are other credit bureau scores although FICO scores are by far the most commonly used. Other credit bureau scores may evaluate a credit report differently than FICO scores. In some cases, a higher score may mean more risk, not less risk as with FICO scores.
An individual's score may be different at each of the three main credit-reporting agencies. The FICO score from each credit reporting agency considers only the data in the credit report at that agency. If a person's current scores from the credit reporting agencies are different, it is probably because the information those agencies have on that person differs.
An individual's FICO score changes over time. As the data changes at the credit-reporting agency, so will any new score based on that credit report. A FICO score from a month ago is probably not the same score a lender would get from the credit-reporting agency today.