English still uses the cognate "strand" to mean beach or riverside. The most famous is The Strand in London, along the Thames. It's a bit archaic sounding but is not too uncommon.
Likely familiar even if you haven't heard "strand" as such with that meaning: "stranded" (run aground on the beach).
One place where you might possibly have heard "strand" meaning the beach: Lewis Carroll. "The Walrus and the Carpenter were walking on the strand: / They wept like anything to see / Such quantities of sand. / 'If this were only cleared away,' / They said, 'it would be grand.'"
The way I (L1-english) have thought usage went is: "beestje" (as in "Huisje, Boompje, Beestje") is informal for animal, but "dier" (as in PvdD*) is formal.
“Beest” is a wild animal, or a savage being. It’s quite similar to English “beast”. “Beestje” is a diminutive that is affectionately applied to animals. “Dier” is neutral (not formal) “animal”.