If you jot something short such as an address somewhere, you write it down so that you will remember it. Could you just jot his name on there. = write Jot down means the same as jot. Keep a pad handy to jot down queries as they occur Listen carefully to the instructions and jot them down. = note down
emphasis If you say that there is not a jot or not one jot of something, you are emphasizing that there is not even a very small amount of it. There is not a jot of evidence to say it does them any good It makes not one jot of difference. = bit. To write down briefly or hastily: jot down an address. jot down to write a short piece of information quickly. not a jot not at all or none at all