10-Letter Words Containing: T,H,I,R,L,_

• To lower the velocity and kinetic energy of fast neutrons in a nuclear reactor by use of a moderator, and thus increase the efficiency of fission

• recurring with measured regularity

• sufficiently valuable to justify the investment of time or interest

• parallel to or in the plane of the horizon or a base line

• something that is oriented horizontally

• someone who writes plays

• the parturition process in human beings; having a baby; the process of giving birth to a child

• in a joyous manner