What is the meaning of 't?

Contraction of it.

Contraction of that.

contraction of het

contraction of dit

contraction of te

contraction of het (“the”)

contraction of het (“it”)

Contraction of ti.

neuter singular of de

the, it

Reduced form of het (“it”)

Reduced form of het (“she”)

alternative form of et

Reduced form of hat (“it”, subject)

Reduced form of hat (“she”, subject)

Reduced form of ham (“it”, object)

Reduced form of ham (“her”, object)

Reduced form of höm (“it”, object)

contraction of at

Source: wiktionary.org