The genitives depending on irritamen and irritamentum in the following examples are not exactly alike, one being concrete and the other abstract; but they are near enough in meaning, and the nouns themselves are used in sufficiently similar contexts to justify us in saying that either one might have been used in place of the other: nisi adiecisset opes, irritamen animi avari, Ov. M. 13, 434; neque salem neque alia irritamenta gulae quaerebant, Sall. Jug. 89, 7.
Levamen and levamentum are used in parallel examples: cuius mali (debt) plebes nullum levamen speraret, Liv. 6, 35, 1; non aliud malorum levamentum quam si linquerent castra, Tac. H. 1, 30, 9.
The verbs used with medicamen and medicamentum show a lack of differentiation between these nouns: quod diceres te violentis quibusdam medicaminibus solere curari, Pis. 6, 13; si eo medicamento sanus factus esset, Off. 3, 92.
The verbs with molimen and molimentum in the following examples are very similar, and there is the same adjective modifying each noun: temptat revellere annosam pinum magno molimine, Ov. M. 12, 357; neque exercitum sine magno commeatu atque molimento in unum locum contrahere posse, B. G. I, 34, 3.
Identity of verbs and the case of momen and momentum show there is no difference in their meaning: momine uti parvo possint impulsa moveri, Lucr. 3, 188; animus paulo momento huc vel illuc impellitur, And. 266.
Parallel instances of blanditia and blandimenta are seen in these examples: haec meretrix meum erum sua blanditia intulit in pauperiem, Truc. 572; illum spero immutari potest blandimentis, oramentis, ceteris meretriciis, Truc. 318; benevolentiam civium blanditiis et adsentando colligere turpe est, Lael. 61; Lepida blandimentis ac largitionibus iuvenilem animum devinciebat, Tac. H. 13, 13.
Adiutorium is a rare word, but in the following examples it is seen to have the same general meaning as adiumentum, “help”: sine adiutorio ignis nihil calidum est, Sen. Ep. 31; neque apud homines res est ulla difficilior neque quae plura adiumenta doctrinae desideret, De Or. III, 84.
Experimentum in the plural naturally means the same as experientia (experience), but in the singular also they both mean a trial or attempt, or the result of trial, proof: debemus temptare experientia quaedam, sequentes non aleam, sed rationem aliquam, Varro, R. R. 1, 18, 8; hoc est maximum experimentum, hanc vim esse non in die positam sed in cogitatione diuturna, T. 3, 74. With the meaning of experience: Agrippa non aetate neque rerum experientia tantae moli par, Tac. A. 1, 4; Metello experimentis cognitum erat, genus Numidarum infidum esse, Sall. Jug. 40, 3.
Firmamen and firmamentum might be interchanged, in both their figurative and literal meanings: ruptosque obliqua per ungues porrigitur radix, longi firmamina trunci, Ov. M. 10, 491; ossa nervique, firmamenta totius corporis, Sen. De Ira, 2, 1, 2. Both the dependent genitives above express concrete objects; in the following they express abstract objects: unicum lapsae domus firmamen, unum lumen afflicto malis temet reserva, Sen. Herc. Fur. 1251; sic ille annus duo firmamenta rei publicae per me unum constituta evertit, Att. I, 18, 3.
Documen occurs only once, but its context shows it to be equivalent in meaning to documentum, which is used in strikingly similar contexts: flammas ut fulguris halent pectore perfixo, documen mortalibus acre, Lucr. 6, 391; ut sint reliquis documento et magnitudine poenae perterreant alios, B. G. 7, 4, 10.