Final answer:
The correct term for a series of characters used to express feelings in email is 'Emoticon'. Emoticons are combinations of keyboard characters, as opposed to graphical emojis, and are often used to convey emotion in text communication.
Step-by-step explanation:
The term used for typed series of printable characters used to signify feelings in email communication is Emoticon. An emoticon is a logographic combination of characters, usually punctuation marks, numbers, and letters, to create a stylized representation of a face expressing an emotion. Unlike emojis, which are graphical images used to express emotions or ideas, emoticons are simple combinations of keyboard characters that mimic facial expressions to convey sentiment in a text-based format. For example, the emoticon :-) represents a smiling face, signifying happiness or approval.