The word “unlocked” in the context of phones usually implies the lack of a carrier lock on the device as originally manufactured and sold. It is not precisely correct to refer to phones originally locked to a carrier as unlocked when offering them for sale without disclosing any original carrier lock, as there are differences in supported frequency bands depending on the jurisdiction the phone was sold in that may make it incompatible with some carriers, whereas “factory unlocked” phones of the same model are usually world band phones and support all common carrier frequencies.
To recap: it’s fine to refer to phones which have had an unlock code applied to them as unlocked. To differentiate phones which came unlocked when originally manufactured, this second group of phones is referred to as “factory unlocked.”
Sorry to be pendantic, and this isn’t directed at OP. Most of this is inside baseball and is only important when buying or selling phones secondhand, in order to make sure the new owner is able to use their phone on a different carrier than the prior owner.
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All of the above is separate to anti-theft locks which are supported by Android and iOS devices, which must be removed before sale in order for the new owner to associate the device with their own personal Google or Apple account, respectively.