Latch onto Definition 1 of 3Pro Tip 1/3New Concepts Use 'latch onto' when you quickly understand or start liking a new idea. She immediately latched onto the new technology. Pro Tip 2/3Mental Commitment Indicates a strong mental engagement or being convinced by an idea. Once he latched onto the notion, there was no changing his mind. Pro Tip 3/3Intellectual Engagement Shows a deep and often sudden engagement with a thought or idea. He read the quote and latched onto its deeper meaning.