What did Lashley's term engram referred to?

Lashley's term "engram" refers to a hypothetical physical representation of memory within the brain. He proposed that an engram is a neural trace or change in the brain that corresponds to the storage of a specific memory, influenced by his research on the effects of brain lesions on learning and memory in rats. Although the exact nature of engrams remains a topic of ongoing research, Lashley's work laid foundational concepts in understanding how memories might be encoded in the brain.