Clearing away all of the prefixes and suffixes from this word bring us down to its root: peleh. And "peleh" has a variety of meanings. In its simplest form, it means to separate. In its more intense form, it means to search. And in its causative form, it has the meaning of wonder or miracle.
It should not be a surprise any religion, ours included, has a variety of words for miracles. Each word has other meanings that give depth and nuance to our understanding. (The same is true of other religious terms, like sin, prayer, and offering – not to mention contribution!) If "nes," which has been previously discussed, is meant to draw our attention to the event in the way a flag captures out attention where it waves, "peleh" (here, "nifla'ah") directs our attention inward.
Fortunately, English expresses the meaning of the word very well. There are two ways to understand the word "wonder." The first is something that is marvelously unusual, as in its use in the legendary "Seven Wonders of the World," or Batman's sidekick, "Robin, the Boy Wonder." This kind of wonder separates the object of wonder from all other objects or people or events. The second meaning is that which provokes curiosity and reflection, as in the famous musical question, "I wonder, wonder who, budooo, who, who wrote the book of love." This kind of wonder is an internal process that leads a person to consider matters that extend from the source of wonder, but are not necessarily apparent. In other words, wonder is separating and wonder is searching.
"Nifla'ot" are those matters that stand out from the rest and inspire us to reflection on larger issues. They are attention-getters and thought-provokers. They ask the questions "what is that" and "how can that be?" If I had to choose a single word, it would be "wonderments."
For his anthology of quotations from Abraham Joshua Heschel, the late Rabbi Samuel Dresner chose the title from the introduction that Heschel wrote to his own book of Yiddish poetry fifty years earlier. "I asked for wonder, not for success, and You gave it to me." Wonders are all around us and within us as well.