Any asset, commodity, or currency that one can use as an exchange for an item of similar value without diminishing its value is defined as a store of value.
Understanding the term
A store of value is a product (a commodity, asset, or currency) that retains its value over time. The actual value of this kind of product could stay unchanged or increase for a certain duration but never decrease.
For example, fruits cannot be considered a good store of value since they are perishable by nature. The imminent decay of such products makes them worthless at some point in the future. Electronics, vehicles, and other items whose value depreciates over time pose the same problem for people looking for the best store of value to invest in.
Since the day it reached its first all-time high, Bitcoin has been considered a worthy store of value, just like gold or oil. Because of its scarcity and durability, Bitcoin is one of the best stores of value.
Precious metals like gold and silver are some examples of a store of value because their prices seem mostly stable with a chance to increase over time but not depreciate. Any product that has a prolonged non-perishable shelf life could be a good store of value.