Much of this entry finds parallels in the scholia to the Aristophanes passage quoted (see n. 2). The headword here is aorist subjunctive active, second person singular, of the verb stomo/w, which is capable of many meanings consistent with its connection to the noun sto/ma ('mouth'), but in this context involving knives and blades, means 'whet' or 'sharpen'. (For related words see sigma 1132 through sigma 1134, as well as sigma 1137 and 1139, particularly the last three.) This form is probably drawn from the quotation given, but in Aristophanes, and in ms G of the Suda, the form is the future indicative (stomw/seis), which is normal in Classical Attic in a o(/pws clause of exhortation, and to which the Suda's stomw/sh|s would have been homophonous in later Greek.
[1] A present indicative verb used to gloss an aorist subjunctive (or future indicative -- see previous note). Probably an error, as a simple change of accent (from parocu/neis to parocunei=s, would change the word to future indicative, and would parallel the tense and mood of the most common gloss in the scholia (o)cu/neis). Two early editions of the Suda print aorist subjunctives here: Chalcocondyles' editio princeps (1499) has parwcu/nh|s [sic] and the Basel edition (1543) parocu/nh|s.
[2] Aristophanes, Clouds 1107-1110, here with minor variants, including stomw/sh|s for stomw/seis (see above); later in the passage the Suda also has the future indicative of the same verb, stomw/seis ['you will whet'], in place of Aristophanes' aorist imperative sto/mwson. This passage is also quoted at omicroniota 5.