“Siddhāṇam Buddhāṇam” is a Jain reverential phrase used for Siddhas and Buddhas.

Meaning

• Siddhāṇam = the Siddhas, the liberated souls
• Buddhāṇam = the enlightened / awakened beings
• Together, it expresses veneration to the spiritually perfect and awakened souls

Jain sense

In Jain Dharma, such words are used with deep respect for:

• the Siddhas who have destroyed all karmas and attained liberation
• the Arhats / Tirthankars and spiritually awakened beings who show the path of liberation

Simple meaning in English

“I bow to the liberated and enlightened souls.”

If you want, I can also give:

• the full stotra text
• its word-by-word अर्थ
• or the relation with Navkar Mantra