Stock and flow

Stock and flow are two ways to measure things. A stock is something that you can measure at a certain point in time and is like a snapshot of an amount. A flow is something that happens over a period of time and is like a running total of an amount. For example, if you own 10 stocks of a company then at any given time you can say you have 10 stocks. The flow of those stocks would be how much you have gained or lost over time depending on how much their value changes.