A monomer represented by Chemical Formula 1: wherein, in Chemical Formula 1, R 1 and R 2 are independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 cycloalkyl group, a substituted or unsubstituted C3 to C30 alkoxy group, a substituted or unsubstituted C3 to C30 cycloalkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 to C30 acyl group, a hydroxy group, a halogen, a nitro group, -NR'R" (wherein R' and R" are independently hydrogen, a C1 to C30 alkyl group, or a C6 to C30 aryl group), -SiR'R"R''' (wherein R', R", and R''' are independently hydrogen, a C1 to C30 alkyl group, or a C6 to C30 aryl group), or a combination thereof, o and p are independently an integer ranging from 0 to 3, L 1 is O or NR b (wherein R b is hydrogen or a C1 to C20 alkyl group), A 1 is a C6 to C30 aromatic organic group, and R a is hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C3 to C30 cycloalkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C7 to C30 arylalkyl group, a hydroxy group, a halogen, a nitro group, -NR'R" (wherein R' and R" are independently hydrogen, a C1 to C30 alkyl group, a C6 to C30 aryl group, or a C7 to C30 arylalkyl group), -CO-NR'R" (wherein R' and R" are independently hydrogen, a C1 to C30 alkyl group, a C6 to C30 aryl group, or a C7 to C30 arylalkyl group), -SiR'R"R''' (wherein R', R", and R''' are independently hydrogen, a C1 to C30 alkyl group, a C6 to C30 aryl group, or a C7 to C30 arylalkyl group), or a group represented by Chemical Formula 2: wherein, in Chemical Formula 2, L 2 and L 3 are independently O, CO, COO, C=C, or CONR b (wherein R b is hydrogen or a C1 to C30 alkyl group), A 2 and A 3 are independently a substituted or unsubstituted C6 to C30 aromatic ring, a substituted or unsubstituted fluorene ring, or a substituted or unsubstituted C7 to C20 arylalkyl group, q and r are independently an integer ranging from 0 to 3, m is an integer ranging from 0 to 3, and n is an integer ranging from 0 to 20. R 1 and R 2 are independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 cycloalkyl group, a substituted or unsubstituted C3 to C30 alkoxy group, a substituted or unsubstituted C3 to C30 cycloalkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 to C30 acyl group, a hydroxy group, a halogen, a nitro group, -NR'R" (wherein R' and R" are independently hydrogen, a C1 to C30 alkyl group, or a C6 to C30 aryl group), -SiR'R"R''' (wherein R', R", and R''' are independently hydrogen, a C1 to C30 alkyl group, or a C6 to C30 aryl group), or a combination thereof, o and p are independently an integer ranging from 0 to 3, L 1 is O or NR b (wherein R b is hydrogen or a C1 to C20 alkyl group), A 1 is a C6 to C30 aromatic organic group, and R a is hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C3 to C30 cycloalkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C7 to C30 arylalkyl group, a hydroxy group, a halogen, a nitro group, -NR'R" (wherein R' and R" are independently hydrogen, a C1 to C30 alkyl group, a C6 to C30 aryl group, or a C7 to C30 arylalkyl group), -CO-NR'R" (wherein R' and R" are independently hydrogen, a C1 to C30 alkyl group, a C6 to C30 aryl group, or a C7 to C30 arylalkyl group), -SiR'R"R''' (wherein R', R", and R''' are independently hydrogen, a C1 to C30 alkyl group, a C6 to C30 aryl group, or a C7 to C30 arylalkyl group), or a group represented by Chemical Formula 2: L 2 and L 3 are independently O, CO, COO, C=C, or CONR b (wherein R b is hydrogen or a C1 to C30 alkyl group), A 2 and A 3 are independently a substituted or unsubstituted C6 to C30 aromatic ring, a substituted or unsubstituted fluorene ring, or a substituted or unsubstituted C7 to C20 arylalkyl group, q and r are independently an integer ranging from 0 to 3, m is an integer ranging from 0 to 3, and n is an integer ranging from 0 to 20.