Orthographical is a tricky word to spell, but it's pronounced /ɔːθəˈɡræfɪkl/. The first syllable is pronounced like the word "orthodox," and the 'o' sound in the second syllable is long. The 'th' in 'ortho-' is voiced like in the word "the," while in 'graphical' it's unvoiced like in "thin." The word 'graphical' ends in a long 'i' sound followed by 'cal.' Overall, the spelling is a combination of Greek and Latin roots, making it a challenge for even the most skilled spellers.
Written with their proper letters; in arch., delineated according to the elevation, not the ground-plot; in geom., consisting of straight lines on a plane at right angles to it.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "orthographical" is derived from the Greek roots "orthos", meaning "correct" or "straight", and "graphia", which means "writing" or "representation". Combining these roots together, "orthographical" refers to something that pertains to correct or accurate writing or spelling.