Step 1 : Introduction to the question "how many tentacles does an octopus have "
The modern convention however, is to speak of appendages as "tentacles" when they have relatively thin "peduncles" or "stalks" with "clubs" at their tips. In contrast the convention refers to the relatively shorter appendages as "arms". By this definition the eight appendages of octopuses, though quite long, count as arms. In terms of this article however, both types of organs count as tentacles because in relevant ways they are structurally and functionally similar.