Will was busy cutting his toast into thin strips and forming rude pictographs out of them.

“What is that supposed to be?” Jem asked curiously. “It looks almost like a -” He glanced up, saw Tessa, and broke off with a grin. “Good morning.

—  Clockwork Prince, the chapter where Jem was about to say dick.

Parabatai,” said Jace. “It means a pair of warriors who fight together—who are closer than brothers. Alec is more than just my best friend. 

 Parabatai ⇒ A pair of Nephilim warriors who fight together as lifelong partners, bound together by oath, regardless of their gender. Their bond is not reflected only in their closeness and willingness to lay down their lives for one another, but also in oath—one sworn in front of the Council.