You look for what again? Unless you have composed an email then there is nothing to send and clicking send, sends the email immediately. There for the is no purpose having a send receive button as there is nothing ever to send unless you specifically go out of your way to use the shortcut keystroke to send later (Ctrl+Shift+Enter). Those that use the outbox to queue mail generally just right click the outbox folder and select send unsent messages.

There is a get mail button offered in the toolbar and also visible in the header of the folder pane. (beside the big blue +New Message button.) It looks like a cloud for some reason.

As so often in IT, there is tripping up over terminology, i.e. different wording for stating the same underlying concept. I used the phrase "Send-Receive" in my question because that is the name of a specific Outlook 2016 client button that I have used for many years for both sending and receiving, so it was very much in my head as the words to use. To shorten my question, I had previously edited out the following: "The context is for example expecting an email to arrive momentarily, e.g. promised immediately on the phone to me by someone just now." I should have left that in my question to indicate that the focus is 100% on the Receive in Send-Receive. My error, over-editing. You solved my problem by pointing out "Get Message", which is in effect the same concept as "Receive" in Outlook 2016 desktop. I just could not easily clear my brain of the familiar wording, a typical issue with changing apps. Thanks for responding. I will mark solved.