arduous, ordinal
Some seven letter words with the second letter A and the third letter U are:bauxitecausticcautiondauphinhaughtyhauntedhauteurlaundrymaudlinnaughtypaunchyraucousraunchysauntersausagevaulted
fasting, wasting, casting
boxtops
freeing, freedom
diddled gagging
devalue
savaged
Maximum.
abilityboilingclinicsdairiesedificefailingglidinghailinginitialjoiningmailingnoisieropinionpricingquinineraisinssuicidetrivialutilityvoidingwriting
The second letter of the seven letter word meaning "one-fourth" is "u." The word is "quarter."u as in quarter
Sincere
U is the second letter in the word quarter.