An antique churn for making butter. The definition of a churn is a device for making butter. An example of a churn is what the Amish use to make butter. To churn is defined as to stir or shake milk or cream with intense movements in the process of making butter, to stir up and agitate, or to produce something at a rapid and regular rate.
Spiders and scorpions are members of one chelicerate group, the arachnids. Scorpions' chelicerae have three sections and are used in feeding. Spiders' chelicerae have two sections and terminate in fangs that are generally venomous, and fold away behind the upper sections while not in use.
Spiders, like most living creatures, are assigned to ranks in what is called a taxonomic hierarchy. Creatures with similar physical characteristics and/or genetic traits are placed alongside one another in each rank. Here is how a thin-legged wolf spider is placed, for example (and yes, spiders are animals):