| A | B |
|---|
| border | a boundary line that divides one country, territory, or state from another |
| boundary | a line or thing that marks a separation or bordercore |
| core | the central part of anything |
| exterior | outer surface |
| hub | center of activity 2. central part of a wheel |
| interior | the inside part of something |
| marrow | the soft substance found inside a bone 2. the central part or most important part |
| midst | the middle or the central part |
| peel | the skin of fruit |
| periphery | an outer boundary, especially of something round |
| pith | the soft spongy tissue in the center of some plant stems |
| pulp | the soft inside part of certain fruits 2. the inner part of a tooth |
| rind | a hard or firm outer layer or coating as on some plants, fruits, or cheeses |
