Definition of aspiration. 1  1a : a strong desire to achieve something high or great an aspiration to become famous âusually plural a young man with political/literary aspirationsb : an object of such desire An acting career is her aspiration.
Wheel and axle. The wheel and axle is one of six simple machines identified by Renaissance scientists drawing from Greek texts on technology. The wheel and axle consists of a wheel attached to a smaller axle so that these two parts rotate together in which a force is transferred from one to the other.
Railroad car wheels are affixed to a straight axle, such that both wheels rotate in unison. This is called a wheelset. A train wheel or rail wheel is a type of wheel specially designed for use on rail tracks. A rolling component is typically pressed onto an axle and mounted directly on a rail car or locomotive or indirectly on a bogie (UK), also called a truck (North America).