http monitor

I'm not certain I'm understanding your question properly but, with what you've provided, I might answer that "http monitor" is a type of BIG-IP monitor test you can configure to check the status of an HTTP pool member, while "http head" is an HTTP method. You can use the HTTP HEAD method in an HTTP monitor test, if using either HTTP 1.0 or HTTP 1.1. See K2167: Constructing HTTP requests for use with the HTTP or HTTPS application health monitor (https://support.f5.com/csp/article/K2167)

The parent monitor with the name http uses 'GET' as the HTTP method, whereas the monitor with the name http_head_f5' uses 'HEAD' as the HTTP method.