Perhaps the largest invertebrate ever known, the giant dinosaur-era octopus lived more than 72 million years ago. This predator dwarfed even the giant marine reptiles, such as plesiosaurs, not to mention today’s largest invertebrate, the giant squid.

3-D: Short for three-dimensional. This term is an adjective for something that has features that can be described in three dimensions — height, width and length. 

artificial intelligence: A type of knowledge-based decision-making exhibited by machines or computers. The term also refers to the field of study in which scientists try to create machines or computer software capable of intelligent behavior.

behemoth: A term for anything that is amazingly big. The term comes from a monstrous animal described in the Bible’s book of Job.

cephalopods: Ocean-dwelling animals that include squid and octopuses.

chitin: A tough, semi-transparent substance that is the main component of the exoskeletons of arthropods (such as insects). A carbohydrate, chitin also is found in the cell walls of some fungi and algae.

colleague: Someone who works with another; a co-worker or team member.

Cretaceous: A geologic time period that included the end of the Age of Dinosaurs. Spanning 145 million to 66 million years ago, it was a time when the whole planet had a relatively mild climate, with forests growing near both the North and South Poles. It marked the emergence of flowering plants and massive volcanic eruptions, which triggered big shifts in ocean ecosystems. And some regions cooled, leading dinosaurs there to adapt by evolving a coat of insulating feathers. Finally, it all came to an end 66 million years ago when a giant meteorite crashed into Earth, changing the global climate overnight. This wiped out all the dinosaurs (except those that would survive as birds), along with half of all plant and animal species.

digital: (in computer science and engineering)  An adjective indicating that something has been developed numerically on a computer or on some other electronic device, based on a binary system (where all numbers are displayed using a series of only zeros and ones).

dinosaur: A term that means terrible lizard. These reptiles emerged around 243 million years ago. All descended from egg-laying reptiles known as archosaurs. Their descendants eventually split into two lines. For many decades, they have been distinguished by their hips. Many large dinosaurs died out around 66 million years ago. But some saurischians lived on. They are now the birds we see today.

ecosystem: A group of interacting living organisms — including microorganisms, plants and animals — and their physical environment within a particular climate. Examples include tropical reefs, rainforests, alpine meadows and polar tundra. The term can also be applied to elements that make up some artificial environment, such as a company, classroom or the internet.

extinct: (n. extinction) An adjective that describes a species for which there are no living members.

food web: (also known as a food chain) The network of relationships among organisms sharing an ecosystem. Member organisms depend on others within this network as a source of food.

fossil: Any preserved remains or traces of ancient life. There are many different types of fossils: The bones and other body parts of dinosaurs are called “body fossils.” Things like footprints are called “trace fossils.” Even specimens of dinosaur poop are fossils. The process of forming fossils is called fossilization.

invertebrate: An animal lacking a backbone. About 90 percent of animal species are invertebrates.

marine: Having to do with the ocean world or environment.

model: A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others.

mosasaur: A type of extinct marine reptile that lived at the same time as dinosaurs.

octopus: (pl. octopi or octopuses) Sea mollusks with a soft, sac-shaped body and eight arms. Two rows of suckers along each arm give the animal an ability to grasp and hold onto things. Cousins of the squids, these animals have a sharp beak-like mouth and good vision.

paleontologist: A scientist who specializes in studying fossils, the remains of ancient organisms.

plesiosaur: A type of extinct marine reptile that lived at the same time as dinosaurs and is noted for having a very long neck.

predator: (adjective: predatory) A creature that preys on other animals for most or all of its food.

range: The full extent or distribution of something. For instance, a plant or animal’s range is the area over which it naturally exists.

reptile: Vertebrate animals belonging to a group known as Reptilia. Most reptiles have skin that is covered with scales or horny plates. Snakes, turtles, lizards and alligators are all reptiles. Once considered their own separate group, birds now belong to this order. With the exception of modern birds, most modern reptiles are cold-blooded (or ectothermic).

sea: An ocean (or region that is part of an ocean). Unlike lakes and streams, seawater — or ocean water — is salty.

shell: The normally hard, protective outer covering of something. It could cover a mollusk or crustacean (such as a mussel or crab), a bird’s egg or some other relatively soft tissue that needs protection (such as a tree nut or peanut).

species: A group of similar organisms capable of producing offspring that can survive and reproduce.

squid: A member of the cephalopod family (which also contains octopuses and cuttlefish). These predatory animals, which are not fish, contain eight arms, no bones, two tentacles that catch food and a defined head. The animal breathes through gills. It swims by expelling jets of water from beneath its head and then waving finlike tissue that is part of its mantle, a muscular organ. Like an octopus, it may mask its presence by releasing a cloud of “ink.”

Jake Buehler is a freelance science writer, covering natural history, wildlife conservation and Earth's splendid biodiversity, from salamanders to sequoias. He has a master's degree in zoology from the University of Hawaii at Manoa.