oxytocin [ok'-si-toh'-suhn] A naturally occurring chemical produced by the body which seems to promote empathy and trust, and influences pair-bonding. The physical effects of oxytocin include increased sensitivity of nerve endings, stimulated muscle contractions, and increased heart rate. The emotional feelings it produces are associated with affection, caring, love, peace, nurturing, security, and attachment, plus an urge to touch and cuddle. It's sometimes known colloquially as "the cuddle chemical."

norepinephrine [nawr--ep-ĭ-nef´rin] A neurotransmitter which induces euphoria in the brain, exciting the body by giving it a booster dose of natural adrenaline. This causes the heart to beat faster and blood pressure to rise. It is similar to adrenaline and many experts believe it helps determine your basic levels of stimulation and arousal. High levels of norepinephrine increase our experience of joy and reduce appetite. It is also associated with focused attention, elevated energy, and elation. High levels of dopamine are also associated with norepinephrine.

vasopressin [vas-oh-pres'-in] Vasopressin has been associated with the formation of long-term, monogamous relationships. Oxytocin and vasopressin interfere with the dopamine and norepinephrine pathways, which might explain why passionate love fades as attachment grows.

braffin [braf'en] (Brit. Obsolete) A horse collar. A device used to distribute a load around a horse's neck and shoulders when pulling a wagon or plough. The collar often supports and pads a pair of curved metal or wood pieces, called hames, to which the traces of the harness are attached.