Merism is a figure of speech in which a combination of two contrasting parts of the whole refer to the whole. It cracked me up to know that this is a word. I don’t know why.
Here is an example, in order to say that someone searched everywhere, the merism “searched high and low” could be used as the expression for searching everywhere! .
Merisms are common in the Old Testament. For example, in Genesis 1:1, when God creates the heavens and the earth the two parts – heavens and earth – refers to the fact that God created everything – the whole universe (aka the heavens and the earth and everything in between) ! There is another example in Psalm 139, where the psalmist declares that God knows “my sitting down and my rising up”. In other words, God knows all the psalmist’s actions.
I have lots of mirm-isms too – but I hope they are not two ends of the spectrum:
back and forth. here and there. high and low. in and out. black and white. now and then. boys and girls. up and down. …