the meaning of AARAJ means the following:

اعرج (a'aaraj), which is the root word: person who has a lame leg from a polio disease.  He walks lamely.  Such person doesn't walk straight. 

العرجان (al-aarajan): مشية الأعرج  (mishyatu al-a'aaraj) the walk of the a'aaraj.      

العرج (al-aaraj):  كالحقب , و هو ان لا يستقيم مخرج البول it means al-haqab, which is when the ejecting of the urine is not straight and is curved (لا يستقيم la yastaqeem).

العرج (al-aaraj): غيبوبة الشمس, و يقال إنعراجها نحو المغرب  the setting of the sun, and it is said: it's inejaajuha towards the West, which means, it's curved or archy path towards the West.    

عَرَجَ (aaraja):  عريج (aareej):  إرتفع و علا  raised and ascended up.

عرّج تعريج (aarraja taareeja):  ميّل (mayyala)  made curvy or archy.

المُنْعَرَجْ (al-munaaraj):  المنعطف (al-munaataf) a curved turn ahead.

[So when Allah Almighty Says: الله ذي المعارج , it means that Allah Almighty is the One who Created the archy and curvy orbits and paths of the Universe.  They are not straight shots!  They are curvy.  That's why Allah Almighty chose the Words  عرج ,  يعرجون , المعارج because they all speak about curvy routes to Heaven and not straight ones.]

Furthermore, we read:

إنعرج الشئ  (in'aaraja al-shaya'): إنعطف و مال يَمْنَةً و يَسْرَةً. يقال: إنعرج النهر.  Something that curved to the right and to the left.  It is said: the river إنعرج (in'aaraja), which means the river curved to the right and to the left.  It is not straight.

تعاريج النهر (ta'aareej al-nahr):  منعطفاته (mun'atafatih) the river's curving points.

عَرَجَ (aaraja): to swerve,  to zigzag, to follow a zigzag course.

تعاريج (ta'aareej): wavy lines.

مُنْعَرَجْ (munaaraj):  zigzag, winding.

So when Allah Almighty Said:

‏36:39 والقمر قدرناه منازل حتى عاد كالعرجون القديم

عرجون is derived from عرج or إنعرج, and it clearly means that the moon's orbit does curve to the right and the left, like the English-letter S!

Remember that the English language, and its letter S were not known to Arabia!  And as our scientists today say that the moon orbits the earth in S-shaped loops, Allah Almighty also Said that the moon orbits the earth in dry and twisted date-tree branches loops, that curve to the right and to the left, which is S-loops.