notebook
n. countable B2 Upper Intermediate Oxford US //ˈnoʊtˌbʊk// UK //nˈəʊtbʊk// note·book
n. a small book with empty pages that you use for writing notes or drawing. It can also mean a small, portable computer.
n. a book with blank or ruled pages for recording information; alternatively, a compact, portable personal computer.
I always carry a notebook to write down my ideas.
She opened her notebook to a fresh page and began sketching the landscape in front of her.
The researcher meticulously logged every observation in a leather-bound notebook, ensuring that no detail of the experiment was lost to memory before the final report was drafted.
From note + book.