element of a cone
— Noun
– English
~ a straight line joining the apex and a point on the base
element of a cylinder
— Noun
– English
~ a straight line running the length of the cylinder
elixir of life
— Noun
– English
~ a hypothetical substance believed to maintain life indefinitely; once sought by alchemists
energy of activation
— Noun
– English
~ the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur; "catalysts are said to reduce the energy of activation during the transition phase of a reaction"
Eleanor of Aquitaine
— Noun
– English
~ queen of France as the wife of Louis VII; that marriage was annulled in 1152 and she then married Henry II and became Queen of England (1122-1204)
eigenvalue of a matrix
— Noun
– English
~ (mathematics) any number such that a given square matrix minus that number times the identity matrix has a zero determinant