A blazing hour is a window hatch (i.e., to close laterally). The word is in the official list of Dutch words. However, it is not or hardly used in the Netherlands. In Belgium, on the other hand, it is a commonly used word, especially in spoken language. In some Flemish dialects, it is also used for shutter.
The word etymology is unclear, although it may be assumed that a French component is in the word.
In the Flemish-born blazer, among other things, paper, and a bark was a large sheet of paper. This resulted in the word blahuur which indicated a paper closure or hatch.
According to Etymological Dictionary Van Dale, 'leaf time' is linked to the medieval Latin 'blaffardus' (of a pale color). is also made to the Middle High German 'bleichvar', 'paint' and 'bleek'.
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