Declension table of ?trisandhya

Neuter	Singular	Dual	Plural
Nominative	trisandhyam	trisandhye	trisandhyāni
Vocative	trisandhya	trisandhye	trisandhyāni
Accusative	trisandhyam	trisandhye	trisandhyāni
Instrumental	trisandhyena	trisandhyābhyām	trisandhyaiḥ
Dative	trisandhyāya	trisandhyābhyām	trisandhyebhyaḥ
Ablative	trisandhyāt	trisandhyābhyām	trisandhyebhyaḥ
Genitive	trisandhyasya	trisandhyayoḥ	trisandhyānām
Locative	trisandhye	trisandhyayoḥ	trisandhyeṣu

Compound trisandhya -

Adverb -trisandhyam -trisandhyāt