The word(s) "invocation" appears 26 time(s) in 26 verse(s) in Quran in Mohsin Khan translation.

(21) And when a wave covers them like shades (i.e. like clouds or the mountains of sea-water), they invoke Allah, making their invocations for Him only. But when He brings them safe to land, there are among them those that stop in between (Belief and disbelief). But none denies Our Signs except every perfidious ingrate.

(22) "No doubt you call me to (worship) one who cannot grant (me) my request (or respond to my invocation) in this world or in the Hereafter. And our return will be to Allah, and Al-Musrifun (i.e. polytheists and arrogants, those who commit great sins, the transgressors of Allah's set limits): they shall be the dwellers of the Fire!

(23) They will say: "Did there not come to you, your Messengers with (clear) evidence (and signs)?" They will say: "Yes." They will reply: "Then call (as you like)! And the invocation of the disbelievers is nothing but in vain (as it will not be answered by Allah)!"

(24) And your Lord said: "Invoke Me, [i.e. believe in My Oneness (Islamic Monotheism) and ask Me for anything] I will respond to your (invocation). Verily! Those who scorn My worship [i.e. do not invoke Me, and do not believe in My Oneness, (Islamic Monotheism)] they will surely enter Hell in humiliation!"

(25) And He answers (the invocation of) those who believe (in the Oneness of Allah - Islamic Monotheism) and do righteous good deeds, and gives them increase of His Bounty. And as for the disbelievers, theirs will be a severe torment.

(26) And who is more astray than one who calls on (invokes) besides Allah, such as will not answer him till the Day of Resurrection, and who are (even) unaware of their calls (invocations) to them?