It can refer to:
* The number two: "Dos" is the more common way to say "two" in Spanish, but "segunda" can be used in certain contexts like "segunda oportunidad" (second chance) or "segunda vez" (second time).
* The day of the week: "Segunda" is also used for Monday, which is the second day of the week in Spanish.
* A specific item: In some cases, "segunda" can be used to refer to the second of something, like "segunda fila" (second row) or "segunda opción" (second option).
The specific meaning of "segunda" will depend on the context of the sentence.