Definition & Meaning of "holy cow"in English

What is the origin of the idiom "holy cow" and when to use it?

Holy cow is an exclamation used to express surprise, amazement, or disbelief. It appeared in American English in the early 20th century as a playful euphemism for "holy Christ," allowing speakers to react strongly without swearing. People used it in newspapers, cartoons, radio, and everyday conversation to convey astonishment or shock in a humorous or emphatic way. Today it is inoffensive, widely recognized, and lighthearted, often adding a fun or dramatic tone to expressions of surprise or amazement.