is said by some to be originally [اِطْمَانَّ] like اِحْمَارَّ, (Mṣb,) as Esh-Shiháb states in the Expos. of the Shifè, (TA,) and to be pronounced with ء for the purpose of avoiding [the combination of] the two quiescent letters, (Mṣb, TA,) anomalously: (Mṣb:) and some say that it is originally اِطْأَمَنَّ, (Mṣb, TA,) because you say طَأْمَنَ الرَّجُلُ ظَهْرَهُ, with ء, (Mṣb,) or, as Suh says, in the R, because it is from تَطأْمَنَ, the م being put before the ء in order to render the word more easy of pronunciation, (TA,) therefore it is anomalous; (Mṣb;) Sb [likewise] held it to be formed by transposition, and derived from طَأْمَنَ; but AA held the contrary to be the case. (TA.)
You say, اِطْمَأَنَّتِ الأَرْضُ, and
↓تَطَأْمَنَت], meaning The land, or ground, was, or became, low, or depressed. (TA.)
See also Q. Q. 2.
اطمأنّ, (Ṣ, Mgh, Ḳ,) inf. n. اِطْمِئْنَانٌ and طُمَأْنِينَةٌ, (Ṣ, Ḳ,) or the latter is a simple subst., (Mgh, Mṣb,) signifies [also] He (a man, Ṣ) was, or became, still, in a state of rest or ease, quiet, or calm; syn. سَكَنَ; (Ṣ, Mgh;) as also اِطْبَأَنَّ, which is formed by permutation. (Ṣ.) And thus it signifies as said of the heart, i. e. It was, or became, still, in a state of rest or ease, quiet, calm, tranquil, unruffled, or free from disquietude. (Mṣb.) Thus too in the saying, اطمأن إِلَى كَذَا, i. e. (tropical:) He trusted to such a thing, or relied upon it, so as to become at rest or ease, or quiet, in mind. (Ḳ, * TA.) And one says also, اطمأنّ جَالِسًا [He became still, or at rest, or at ease, sitting]: (TA:) and اطمأنّ بِنَا الجُلُوسُ [lit. The sitting became still, or free from disquiet, with us]; meaning اِسْتَقْرَرْنَا وَسَكَنَّا فِى الجُلُوسِ [i. e. we became settled, or at rest or ease, and still, in the sitting; or became seated at ease]. (Ḥar p. 280.) And اطمأنّ بِالمَوْضِعِ [He settled in the place; i. e.] he remained, stayed, abode, or dwelt, in the place, and took it as his home. (Mṣb.) And اطمأنّ عَمَّا كَانَ يَفْعَلُهُ (assumed tropical:) [He became at rest from that which he was doing;] i. e. he desisted from that which he was doing. (TA.) And
↓فِيهِ تَطَامُنٌ [or
↓تَطَأْمُنٌ] In him is quietness, calmness, or sedateness. (TA.)