In this page:
https://www.elastic.co/guide/en/elasticsearch/reference/2.4/mapping-date-format.html
We say:
"Many APIs which support date values also support date math expressions, such as now-1m/d — the current time, minus one month, rounded down to the nearest day."
But I think that example with a lowercase "m" is actually "the current time, minus one MINUTE, rounded down to the nearest day."