To learn by heart (or know by heart) means to memorize something completely and thoroughly, so that it can be recited, written, or performed perfectly from memory without looking at notes.
Common variations: Know by heart, learn off by heart (British English), commit to memory
“By Heart” vs. “Off by Heart” vs. “By Hard”
Depending on region and background, learners frequently encounter several variations:
- Learn / Know by Heart: The standard form used in both American and British English (e.g., “She knows the entire poem by heart”).
- Off by Heart: A very common variation in British, Australian, and Commonwealth English (e.g., “I learned my times tables off by heart in primary school”).
- “By Hard” (Mistake): Non-native speakers sometimes mishear the phrase as “learn by hard.” This is an eggcorn/mishearing; the correct word is always heart.
Origin: Why Do We Say “Heart” Instead of “Brain”?
Our brains house our memories, so why would English say you learn something “by heart” rather than “by brain”?
The Ancient “Cardiocentric” Belief
Before modern neuroscience, ancient civilizations believed that the human heart was the physical seat of thought, reason, emotion, and memory (a theory known to historians as the cardiocentric hypothesis):
- Ancient Egypt: The Egyptians believed the heart recorded all of a person’s deeds and memories throughout life. In mummification, the heart was carefully preserved so it could be weighed in the afterlife, while the brain was considered useless and discarded.
- Ancient Greece: Philosophers like Aristotle argued that the heart was the primary organ of sensation, intelligence, and cognitive retention.
Old French and Middle English (1300s)
In medieval Europe, this physiological concept was reflected across many languages. English adopted the phrase in the 14th century as a direct translation (a loan translation or calque) of the Old French expression par cœur (“by heart”).
One of the earliest recorded appearances in English literature is found in Geoffrey Chaucer’s Troilus and Criseyde (c. 1385), where characters speak of reciting texts and prophecies accurately “by heart.”
“By Heart” vs. “By Rote”
While both expressions refer to memorization, they carry distinct connotations in modern education:
- By Heart: Suggests deep, complete mastery and seamless recall. It often implies a personal connection, dedication, or artistic mastery (such as an actor memorizing a script or a child memorizing a favorite song).
- By Rote: Refers to mechanical, repetitive memorization without necessarily understanding the underlying meaning or principles (e.g., memorizing math formulas purely to pass a test).
Sentence Examples
“The pianist played the entire concerto by heart without glancing at the sheet music.”
“In elementary school, we had to learn the Gettysburg Address by heart.”
“I’ve called that phone number so many times that I know it by heart.”
“She practiced her wedding vows until she could recite every word off by heart.”
Similar and Related Expressions
- Know Something Like the Back Of One’s Hand: To be thoroughly familiar with something, to have intimate or detailed knowledge of a topic or location, or to understand something perfectly.
- Commit to Memory: A more formal way of saying to memorize something thoroughly.
- Word for Word / Verbatim: Reciting or copying something exactly as spoken or written.
- Second Nature: An acquired habit or knowledge so deeply ingrained that it is automatic.
- Down Pat: Having something mastered or completely memorized through practice.
- Know (something) Inside Out: To have complete, thorough, and detailed knowledge of something.
- Know Backwards and Forwards: To know a subject or text so completely that you could recite or explain it in any order without hesitation.