According to someone, from vaayu- and skanda-puraaNa: alpAkSaram asandigdhaM sAra-vat vizvato-mukham astobham anavadyaM ca sUtraM sUtra-vido viduH
The translation on that site seemed rather "scarce". Perhaps "everyone" might try to come up with their own translation. Vocabulary alpaakSaram -- [my guess] "smallsyllable(d)": most probably a bahuvriihi meaning 'having only a few syllables' asaMdigdha mfn. not indistinct MBh. xii ; undoubted , unsuspected , certain Jain. (Pra1kr2it {-diddha}) ; Pat. ; ***(%{am}) ind. without any doubt , certainly Pan5cat. Ma1rkP*** sAravat mfn. hard , solid , firm , strong , steadfast MBh. R. &c. ; substantial , nourishing (as food) Car. ; valuable , precious MBh. Ka1m. ; having pith or sap , containing resin Sus3r. ; anavadya mf(%{A4})n. irreproachable , faultless ; unobjectionable ; (%{A}) f. N. of an Apsaras. vizvatomukha [z = sh -- card] (%{-zva4to-}) mfn. facing all sides , one whose face is turned everywhere RV. AV. MBh. &c. ; (%{am}) ind , in every direction BhP. ; m. N. of the sun MBh. astobham -- prolly opposite of 'stobham' stobha m. a chanted interjection in a Sa1man (such as %{hum} , %{ho} , %{oha} &c.) , hum , hurrah , hymn Br. S3rS. MBh. BhP. ; a partic. division of the Sa1ma-veda (q.v.) ; torpor , paralysis = %{ceSTA-vighAta} Nalac. ; disrespect , contumely (= %{helana}) L. NB. Because 'suutram' is a neuter gender word, thus having the ending -m even in the nominative singular case, it's impossible to say, whether some of those other forms ending in -m are agreeing with 'suutram', or indeclinable (ind.), adverb like forms. Totally up to anyone to decide which one is the case... So, a translation might start for instance like this: Knowers of suutras (suutra-vidah) know (viduH) a suutra (to be, or stuff) alpaakSaram, etc.