はず， 筈， 弭
1. should (be), bound (to be), expected (to be), must (be)
2. nock (of a bow)
3. nock (of an arrow)
4. nock-shaped grip (between thumb and forefinger)
5. wooden frame on the tip of the mast of a Japanese ship that prevents the hawser from falling out...
应该（是），必须（是）