faithfulness, loyalty, devotedness / hardworkingness, painstakingness, diligence / healthiness, fitness

epicenter(AmE), epicentre(BrE) - the point on the Earth's surface directly above the focus of an earthquake. / (figuratively) The focal point of any activity, especially if dangerous or destructive .

(agriculture) damage by plant disease and plant pest - major issues in agriculture

earth science

intellectual / the intelligentsia

(organic chemistry) polyethylene

a coach (trainer)

middle, midway

the middle 10 days of the month

neutrality