This might be a bit confusing so let me give an example. Let's take a word, say beer. We can spell by moving the B pawn (b3) or a Bishop (Bc4). We can spell the 2 E's by moving any piece on the E rank (e4,Qe4,Ke4,Ne4,Be4,Re4). Last but not least we can spell R with a rook move (Ra4).
This might be a bit confusing so let me give an example. Let's take a word, say beer. We can spell by moving the B pawn (b3) or a Bishop (Bc4). We can spell the 2 E's by moving any piece on the E rank (e4,Qe4,Ke4,Ne4,Be4,Re4). Last but not least we can spell R with a rook move (Ra4).