突

to grind up; to grind down; to pound; to crush; to mash; to stamp (ore)

spinneret (of a spider)

the most trying spot or period; the most difficult period

xiphoid process; ensiform cartilage

to knock (a person) down

mastoid

constant quarreling; constant quarrelling; bickering; wrangling

dendrite; dendron

Sumo

thrusting down one's opponent either inside or outside the ring

Large Hadron Collider; LHC

Medicine

sudden deafness; SD; sudden sensorineural hearing loss; SSHL

clash of civilizations

Internet slang

flooding a company, organization etc. with phone complaints (usu. loosely organized on anonymous online message boards)

Medicine

roseola; exanthem subitum; roseola infantum; sixth disease; three-day fever

prop; support

sudden and dramatic event (incident); sudden and strange phenomenon

stack effect; chimney effect

overcoming a difficulty; breaking through a barrier; clearing a hurdle

Medicine

sudden infant death syndrome; SIDS; cot death; crib death

mutationism

Genetics

gene mutation

colliding-beam accelerator; (particle) collider accelerator

very edge; far border

crisis relief