The phrase "a back post" is correct and usable in written English.
It can be used in contexts related to construction, fencing, or knitting, where it refers to a specific type of post or stitch.
Example: "To secure the fence properly, make sure to install a back post at each corner."
Alternatives: "a rear post" or "a support post".
There was a back post save from Christian Benteke when Rodgers already had his arms in the air to celebrate.
Yedlin had to be alert on the line to head clear as A back post header from Jewsbury looped towards the far post.
Altidore had scored in every play-off round coming into the final, but looked a less sure presence in the first half, passing up a few decent chances, including a back post header at the half hour mark.
Milner forced a good save from Tomasz Kuszczak on 16 minutes but not until the very end, when Richard Dunne misjudged a back post header that might have taken the game to extra-time did Villa really put pressure on the United goal.
The defenders still struggle mightily on set pieces: After finally notching the tying goal against Chicago last weekend, the club left Fire CB Bakary Soumare wide open for a back post header in stoppage time that required a Save of the Week contender by Portland GK Donovan Ricketts to avoid losing to a 10-man side.
Lafferty scored the opener in the 24th minute with a back post header after Kevin Deery's free-kick.
There was an improvement of sorts after the third goal and Peter Crouch should have scored from a back-post header when Lennon crossed after 28 minutes.
Mark Hughes twice posed a threat from close range, planting a back-post header at Banks and clipping over from a drilled Marcus Bent cross.
Arsenal were never really in danger of facing an upset once they had gone ahead through Podolski's neat angled finish on 15 minutes, which was doubled before half-time with a back-post header.
Kim hadn-sung had a back-post header hacked clear by Sandro after a fine turn in the area by Nam Tae-hee and was put through by a lovely chip from Ji.
The size of Andrew and York's two centre-backs meant they looked a threat from dead-ball situations too and Maxwell breathed a sigh of relief when his defenders were able to clear after he floundered at a back-post set piece.
