According to Walde's Etymological Dictionary, Latin spēs is cognate with spatium and with Old Church Slavonic spěchĭι. Under spatium he refers us to Skt. sphāyati, ‘swells out,’ ‘grows out,’ sphīta, ‘fat,’ ‘flourishing,’ and a number of Baltic-Slavonic and Germanic words, from which I will select O.E. spēd, ‘speed,’ and Lith. spēti, ‘have time for something,’ ‘to be quick enough.’ In place of this etymology I venture to suggest that spēs must be connected with another Lithuanian spēti, which is duly recorded in Lalis's Lithuanian-English Dictionary. It means ‘guess,’ ‘conjecture,’ or ‘suppose,’ and occurs not only uncompounded, but also in the compound , ‘guess,’ ‘divine,’ ‘solve’ (a riddle). The Lat. spes means no doubt ‘hope,’ but it also means ‘expectation,’ which comes nearer to the meaning of the Lithuanian words.