For example, the words Islam, Muslim (one who follows the religion of Islam), salaam (peace), tasleem (submission), silm (peace treaty), and salamah (well-being and wholeness) all come from the same three-letter root (سلم sa-li-ma). While one may translate ‘Muslim’ simply as one who follows the religion of Islam, it has linguistic connections with these other words that give it the connotation of peace, submission, wholeness, and so on. Similarly, the word we commonly translate as faith (إيمان iman) is connected to the words to trust, to be secure, to be in safety, and covenant and pledge, that are all naturally connoted in the Arabic word iman.
Some other interesting examples:
◊ The word for a mother’s womb (رحم rahim) is connected to the word for loving mercy (رحمة rahma).
◊ The word for beauty and perfection (إحسان ihsan) is connected to the word for a good deed, and the reward of a goodly deed (حسنة hasana).
◊ The word for a righteous person (صالح salih) is related to words that mean to make amends, to rebuild or reconstruct, to bring together and to be a peacemaker.
◊ The word for God-consciousness (تقوى taqwa) is related to the word for a shield or protection (وقاية wiqaya), perhaps indicating that remembrance of God can be a spiritual shield for a person, protecting them from harm.
◊ A really interesting example is in the connection between the word for human being (إنسان insaan) and the root أنس aa-ni-sa, which refers to familiarity, companionship and being on close or intimate terms with another. This emphasizes the innately social nature of human beings and our desire to have familiarity and companionship with others, and on a more spiritual level, an innate desire for closeness with the Divine.
Some linguists alternatively trace the word insaan back to the verb that means ‘to forget’ (from the trilateral root نسي na-si-ya), which suggests that it is an innate part of human nature to forget and to sometimes make mistakes.
In studying the trilateral etymology of Arabic, one can really find many beautiful meanings and lessons in the connections between words. In the same way meeting someone’s family can help you understand a person more fully and their nature and personality, getting to know an Arabic word’s ‘family’ can help you discover new dimensions and depths to their meaning.
Stay tuned for upcoming posts, in which I’ll explain why Arabic is the ideal language for poets and lovers. :)
 The latter opinion has been attributed to Ibn Abbas in many works of Quranic exegeses, while the former seems to be the opinion of the authors of Lisan al-‘Arab and Qamus al-Muheet as well as others. (See Lisan al-‘Arab under the entry for “أنس”)